WEBVTT 00:00:00.000 --> 00:00:02.960 so how it's possible that some athletes are swearing 00:00:02.960 --> 00:00:05.799 that it makes them recover faster and make them 00:00:05.799 --> 00:00:08.720 makes them better athletes yeah so there is a 00:00:08.720 --> 00:00:12.060 bit of a difference in the context so for example 00:00:12.060 --> 00:00:15.740 cold kind of like an analgesic effect so it can 00:00:15.740 --> 00:00:19.219 reduce pain so and because of that it also has 00:00:19.219 --> 00:00:22.820 quite a strong placebo effect probably. So if 00:00:22.820 --> 00:00:25.239 you look at, for example, next day performance, 00:00:25.739 --> 00:00:29.039 quite often you can see indeed sometimes a bit 00:00:29.039 --> 00:00:32.179 of a better performance, but that increase in 00:00:32.179 --> 00:00:35.179 performance doesn't really seem to be very different 00:00:35.179 --> 00:00:38.979 than just normal placebo effect. So it's a bit 00:00:38.979 --> 00:00:41.640 difficult to really say whether it's really the 00:00:41.640 --> 00:00:45.799 cooling that has any beneficial effects on, let's 00:00:45.799 --> 00:00:48.439 say, next day performance or... It's just because 00:00:48.439 --> 00:00:50.640 they think they will have better performance. 00:00:50.820 --> 00:00:54.460 You go into the ice bath and you think, okay, 00:00:54.539 --> 00:00:57.560 this will help my recovery and tomorrow I can 00:00:57.560 --> 00:01:01.039 deliver better, I can perform better. Yeah, it's 00:01:01.039 --> 00:01:05.689 difficult to really say that. Hi Milan, it's 00:01:05.689 --> 00:01:08.030 my pleasure to have you on Evidence Strong Show. 00:01:08.150 --> 00:01:10.030 If you could briefly introduce yourself. Thank 00:01:10.030 --> 00:01:12.030 you. Thanks for having me. So my name is Milan 00:01:12.030 --> 00:01:15.629 Metz. I'm a PhD researcher at Maastricht University 00:01:15.629 --> 00:01:19.469 at the M3 Research Group, Muscle Metabolism Maastricht. 00:01:19.689 --> 00:01:22.810 Let's say the main focus of my research is the 00:01:22.810 --> 00:01:25.409 muscle microvasculature, so like the smallest 00:01:25.409 --> 00:01:27.769 blood vessels in the muscle, and specifically 00:01:27.769 --> 00:01:31.230 how they, or like their role in muscle adaptation. 00:01:32.189 --> 00:01:35.310 or muscle recovery. A big part of my PhD work 00:01:35.310 --> 00:01:38.209 is also actually focused on the elderly, so age 00:01:38.209 --> 00:01:40.230 -related muscle loss. But I had the opportunity 00:01:40.230 --> 00:01:43.430 to do a little bit of a sidestep, side project 00:01:43.430 --> 00:01:46.209 to look at the cold water immersion and more 00:01:46.209 --> 00:01:50.129 muscle recovery in young, active people. So that 00:01:50.129 --> 00:01:52.840 was actually quite a nice... Kind of like a side 00:01:52.840 --> 00:01:55.700 project. Excellent. Very grateful for side projects 00:01:55.700 --> 00:01:59.500 of M3 group. We're talking cool water immersion 00:01:59.500 --> 00:02:04.280 and recovery from exercise. So let's go through 00:02:04.280 --> 00:02:06.640 some kind of definitions so we are on the same 00:02:06.640 --> 00:02:10.060 page. So what cold water immersion is? Yeah, 00:02:10.080 --> 00:02:13.300 so for us, it really just means that you are 00:02:13.300 --> 00:02:17.539 submerging into very cold water. And in this 00:02:17.539 --> 00:02:21.099 case, we used eight degrees, which is definitely... 00:02:21.419 --> 00:02:24.259 Very, very cold. So to do that, we also had like 00:02:24.259 --> 00:02:27.439 a big, big ton full of water. And you just have 00:02:27.439 --> 00:02:30.580 to like dump like five big buckets of ice in 00:02:30.580 --> 00:02:33.699 to get to the eight degrees. So it's definitely 00:02:33.699 --> 00:02:37.759 cold. Let's start with what was the aim of the 00:02:37.759 --> 00:02:40.280 study? Because cold water is one and recovery. 00:02:40.400 --> 00:02:42.400 But like, how were you thinking what you were 00:02:42.400 --> 00:02:44.539 the most interested in? Yeah, I mean, one of 00:02:44.539 --> 00:02:47.680 the main reasons to do research in this topic 00:02:47.680 --> 00:02:50.759 is still because it's very, very popular. and 00:02:50.759 --> 00:02:53.060 a lot of people are still doing it. And there's 00:02:53.060 --> 00:02:56.300 still, yeah, this idea that it can improve muscle 00:02:56.300 --> 00:02:59.080 recovery. But yeah, more and more work is now 00:02:59.080 --> 00:03:02.699 showing kind of the opposite effect, that it 00:03:02.699 --> 00:03:05.919 could maybe be bad for recovery. And that's also 00:03:05.919 --> 00:03:08.500 what my colleague Kas Fuchs shown, that if you 00:03:08.500 --> 00:03:11.039 put one leg into the cold water immersion, so 00:03:11.039 --> 00:03:14.219 ice water, compared to just thermal neutral water, 00:03:14.419 --> 00:03:17.439 you see a reduction in muscle protein synthesis. 00:03:17.740 --> 00:03:19.930 And this is the essentially kind of like... an 00:03:19.930 --> 00:03:23.009 underlying process that helps muscles to adapt 00:03:23.009 --> 00:03:25.849 to exercise. So it's also one of the main, let's 00:03:25.849 --> 00:03:28.469 say, mechanisms behind muscle growth. So we think 00:03:28.469 --> 00:03:30.889 that's an important part of muscle recovery. 00:03:31.189 --> 00:03:33.889 Could you explain a little bit more about the 00:03:33.889 --> 00:03:36.810 hypothesis, how you think the adaptation and 00:03:36.810 --> 00:03:40.090 recovery works on the muscle level? Yeah. So 00:03:40.090 --> 00:03:42.370 you mean specifically with cold motor immersion 00:03:42.370 --> 00:03:44.310 or just in general? Maybe let's start in general. 00:03:44.469 --> 00:03:47.330 It's probably good to realize that our muscles 00:03:47.330 --> 00:03:50.569 are not static. And what I mean by that is that 00:03:50.569 --> 00:03:53.210 they're basically constantly turning over. So 00:03:53.210 --> 00:03:55.969 all the building blocks of your muscle, so the 00:03:55.969 --> 00:03:59.139 muscle proteins, they're essentially... every 00:03:59.139 --> 00:04:02.599 day at every moment they are breaking down and 00:04:02.599 --> 00:04:05.000 building back up and because it's doing that 00:04:05.000 --> 00:04:09.080 if you stimulate muscles for example with exercise 00:04:09.080 --> 00:04:13.159 or with nutrition it responds by building more 00:04:13.159 --> 00:04:16.279 than it's breaking down so then because of the 00:04:16.279 --> 00:04:19.360 balance the balance would then be positive then 00:04:19.360 --> 00:04:21.800 you can build muscle over time and that is what 00:04:21.800 --> 00:04:24.819 we think is just like an important concept from 00:04:24.819 --> 00:04:27.420 muscle adaptation also for example if you want 00:04:27.420 --> 00:04:29.819 to grow muscles or get stronger, you would like 00:04:29.819 --> 00:04:33.040 to be in a positive balance. So you want the 00:04:33.040 --> 00:04:36.350 synthesis to be larger than. the breakdown that's 00:04:36.350 --> 00:04:38.290 kind of the idea of muscle protein synthesis 00:04:38.290 --> 00:04:41.430 and then yeah we have already shown a couple 00:04:41.430 --> 00:04:44.430 years back that cold water immersion can reduce 00:04:44.430 --> 00:04:46.990 muscle protein synthesis and that actually also 00:04:46.990 --> 00:04:50.709 aligns quite well with some work from from other 00:04:50.709 --> 00:04:53.490 people showing that if you do cold water immersion 00:04:53.490 --> 00:04:56.790 frequently during let's say i think they did 00:04:56.790 --> 00:04:59.170 a 10 week 12 week resistance training program 00:04:59.170 --> 00:05:04.029 you also see less gains in muscle mass and muscle 00:05:04.029 --> 00:05:06.290 strength So yeah, it does definitely seem that 00:05:06.290 --> 00:05:09.009 cold water immersion can have some kind of negative 00:05:09.009 --> 00:05:13.550 impact on recovery and adaptation. And from the 00:05:13.550 --> 00:05:16.370 study that my colleague did, we weren't really 00:05:16.370 --> 00:05:20.149 sure what was the main mechanism behind it. So 00:05:20.149 --> 00:05:22.350 we saw a reduction in muscle protein synthesis. 00:05:23.050 --> 00:05:25.949 but we weren't really too sure about what was 00:05:25.949 --> 00:05:29.029 really causing the effect. So that's why we came 00:05:29.029 --> 00:05:30.889 up with this follow -up study. And it's actually 00:05:30.889 --> 00:05:34.110 kind of a coincidence because for another project 00:05:34.110 --> 00:05:36.209 that I've been doing at the start of my PhD, 00:05:36.430 --> 00:05:39.389 we introduced a new method in our lab. And it's 00:05:39.389 --> 00:05:42.589 a method with using ultrasounds. Using that method, 00:05:42.649 --> 00:05:46.350 you can assess blood flow in the microvasculature. 00:05:46.449 --> 00:05:49.029 So in the very, very smallest muscle vessels 00:05:49.029 --> 00:05:52.110 of the muscle. So we now had this method and 00:05:52.110 --> 00:05:54.259 then we... thought wow that's that would be perfect 00:05:54.259 --> 00:05:57.600 to use in in this cold water immersion protocol 00:05:57.600 --> 00:06:00.740 because yeah we do think that it probably has 00:06:00.740 --> 00:06:03.899 to be related to to some kind of reduction in 00:06:03.899 --> 00:06:06.360 blood flow just because yeah in the cold you 00:06:06.360 --> 00:06:08.860 have you have vasoconstriction so blood vessels 00:06:08.860 --> 00:06:12.779 they they go well they tighten up basically. 00:06:12.959 --> 00:06:15.779 So this would then be kind of like a really nice 00:06:15.779 --> 00:06:19.040 technique to really investigate like blood flow 00:06:19.040 --> 00:06:21.240 within the muscle. And then again, how that relates 00:06:21.240 --> 00:06:25.060 to recovery. And in this case, we wanted to look 00:06:25.060 --> 00:06:28.160 at how, let's say the amino acids from a drink. 00:06:28.670 --> 00:06:30.930 So that's basically just the building blocks 00:06:30.930 --> 00:06:33.069 from protein. How they ended up in the muscle. 00:06:33.170 --> 00:06:36.449 We just gave him a drink and it had also, we 00:06:36.449 --> 00:06:38.689 call it a tracer. So it's kind of like a special 00:06:38.689 --> 00:06:41.649 amino acid. So building block of muscle protein. 00:06:41.829 --> 00:06:44.310 And then just after a couple hours, we take a 00:06:44.310 --> 00:06:46.410 piece of muscle tissue out of the leg. And then 00:06:46.410 --> 00:06:49.310 we can measure how much of that drink actually 00:06:49.310 --> 00:06:52.189 ended up in the muscle. Okay, so we have your 00:06:52.189 --> 00:06:55.569 goal of the study. You want to be sure. So you 00:06:55.569 --> 00:06:59.040 asked people to drink a tracer. protein so traced 00:06:59.040 --> 00:07:02.240 drink with traced amino acids so the building 00:07:02.240 --> 00:07:05.220 blocks for the muscle as the to exercise yeah 00:07:05.529 --> 00:07:07.829 So we did... Rest is first, then exercise? No, 00:07:07.850 --> 00:07:10.810 we first did the exercise because we also wanted 00:07:10.810 --> 00:07:14.509 to see just the effect of the exercise on blood 00:07:14.509 --> 00:07:18.050 flow. Okay. So that's why we first started with 00:07:18.050 --> 00:07:19.970 just... We did all the measurements from blood 00:07:19.970 --> 00:07:22.529 flow with the ultrasound when they were just 00:07:22.529 --> 00:07:25.009 resting in the bed. Then we did the exercise, 00:07:25.189 --> 00:07:28.029 which was leg press and leg extension. And then 00:07:28.029 --> 00:07:32.170 four sets of 8 to 10 reps with 80 % Bono Ram. 00:07:32.310 --> 00:07:36.629 It was pretty heavy. And right after, we would 00:07:36.629 --> 00:07:39.589 again measure all the blood flow measurements 00:07:39.589 --> 00:07:43.490 just to see the increase in blood flow. And then 00:07:43.490 --> 00:07:46.370 we would do the cold water immersion and then 00:07:46.370 --> 00:07:50.029 again measure blood flow to see specifically 00:07:50.029 --> 00:07:52.730 the effect of the cold water immersion. And then 00:07:52.730 --> 00:07:55.189 they would have the drink and then they would 00:07:55.189 --> 00:07:58.949 just lay in bed for another four hours. And then 00:07:58.949 --> 00:08:01.730 at the end of the four hours, we would take like 00:08:01.730 --> 00:08:04.980 the little piece of muscle and then... like from 00:08:04.980 --> 00:08:06.839 both legs and then see if there were differences. 00:08:07.019 --> 00:08:09.639 I love this design. Thank you. Awesome. So the 00:08:09.639 --> 00:08:12.480 last piece of information we need is who were 00:08:12.480 --> 00:08:15.500 the participants? Yeah, so I did actually similar 00:08:15.500 --> 00:08:18.699 participants as Gus did, just to also make sure 00:08:18.699 --> 00:08:21.759 that, yeah, we would again see a similar effect, 00:08:21.939 --> 00:08:24.620 but then we could combine it with all the measurements 00:08:24.620 --> 00:08:27.860 from blood flow. So it was basically just young 00:08:27.860 --> 00:08:31.360 male adults that were active. So they were definitely 00:08:31.360 --> 00:08:34.320 exercising a couple of times. I believe the average 00:08:34.320 --> 00:08:36.940 was exercising four times per week and doing 00:08:36.940 --> 00:08:40.519 all kinds of sports, but they were not doing 00:08:40.519 --> 00:08:44.419 resistance training on a very structured regular 00:08:44.419 --> 00:08:47.220 basis. So it was more like we had a lot of team 00:08:47.220 --> 00:08:51.330 sport athletes. So people playing football or 00:08:51.330 --> 00:08:53.710 something. And then they were familiar with going 00:08:53.710 --> 00:08:56.909 to the gym maybe once in a while, but they weren't 00:08:56.909 --> 00:09:00.090 really following a really structured three times 00:09:00.090 --> 00:09:03.350 per week or even more resistance training program. 00:09:03.629 --> 00:09:06.809 So did you test what the one repetition maximum 00:09:06.809 --> 00:09:10.090 was? Did you test them? Yeah. Okay. Yeah. Yeah. 00:09:10.149 --> 00:09:13.070 So that was at the very first time that someone 00:09:13.070 --> 00:09:15.870 comes into the lab, we do a screening session. 00:09:16.049 --> 00:09:18.450 So in that screening session, you also... have 00:09:18.450 --> 00:09:21.309 like a medical questionnaire to see whether they're 00:09:21.309 --> 00:09:24.210 really fit or fit enough to participate in the 00:09:24.210 --> 00:09:27.590 study. And there's no maybe medical issues or 00:09:27.590 --> 00:09:30.149 medical issues that maybe could influence your 00:09:30.149 --> 00:09:32.389 results. And then also part of that screening 00:09:32.389 --> 00:09:35.710 session was to test the 1RM on the leg press 00:09:35.710 --> 00:09:37.830 and leg extension. And then we could use that 00:09:37.830 --> 00:09:40.850 during the actual test day. I should think a 00:09:40.850 --> 00:09:43.610 little bit more about the muscle samples for 00:09:43.610 --> 00:09:46.370 people who are not familiar. How does that look 00:09:46.370 --> 00:09:49.600 like? Yeah. It sounds quite, how do you say it? 00:09:49.639 --> 00:09:54.039 It sounds a bit scary maybe, but it's not as 00:09:54.039 --> 00:09:57.000 bad as it sounds. And I can speak from experience 00:09:57.000 --> 00:10:00.019 because I've had 10 taken out of my legs. So 00:10:00.019 --> 00:10:02.779 I have some experience with having muscle biopsies 00:10:02.779 --> 00:10:06.379 taken from my leg. But so how the procedure works 00:10:06.379 --> 00:10:09.500 is that it is performed by a medical doctor and 00:10:09.500 --> 00:10:13.100 they put anesthetic. In the skin and in the muscle. 00:10:13.240 --> 00:10:16.019 And that's usually the most. Let's say annoying 00:10:16.019 --> 00:10:18.460 part. Because yeah putting an anesthetic in. 00:10:18.600 --> 00:10:22.440 That can be painful. Just for maybe like a couple 00:10:22.440 --> 00:10:24.820 seconds. Kind of like a sharp pain. But quite 00:10:24.820 --> 00:10:27.299 quickly that goes away. Because then everything 00:10:27.299 --> 00:10:30.460 is just numb. So actually the whole procedure. 00:10:30.519 --> 00:10:34.419 Of then with the scalpel. Making a small incision. 00:10:34.460 --> 00:10:38.320 Just a centimeter. And then putting like a hollow 00:10:38.320 --> 00:10:41.360 needle in. And we're basically. Yeah, sucking 00:10:41.360 --> 00:10:44.360 a little bit of muscle tissue into the needle 00:10:44.360 --> 00:10:47.740 and then cutting it off. All of that you don't 00:10:47.740 --> 00:10:51.399 really feel, actually, just because of the anesthetic. 00:10:51.620 --> 00:10:55.279 So, yeah, actually, most people who participate 00:10:55.279 --> 00:10:57.759 in our studies, after having the muscle biopsy 00:10:57.759 --> 00:11:00.580 taken, they're like, oh, that actually wasn't 00:11:00.580 --> 00:11:04.279 too bad. I expected worse. But then that piece 00:11:04.279 --> 00:11:07.720 of muscle we can then freeze and later do all 00:11:07.720 --> 00:11:11.690 kinds of analyses on. So these heroes, Gabe, 00:11:11.750 --> 00:11:13.450 how many did you have? How many participants? 00:11:13.870 --> 00:11:19.220 Twelve. 12 male heroes agreed to the horrendous 00:11:19.220 --> 00:11:22.679 protocol of doing it first, then freezing of 00:11:22.679 --> 00:11:26.740 one of their legs and then lying flat for four 00:11:26.740 --> 00:11:31.120 hours for you to punch them with the needle in 00:11:31.120 --> 00:11:34.179 the thigh and take the samples. Was it vastus 00:11:34.179 --> 00:11:38.779 lateralis? Yes. Also because that's just the 00:11:38.779 --> 00:11:42.419 safest muscle to take biopsies from because it's 00:11:42.419 --> 00:11:44.629 on the outside of the upper leg. There's like 00:11:44.629 --> 00:11:49.590 no major arteries or major nerves close to it. 00:11:49.690 --> 00:11:52.169 So that's actually the main reason also why we 00:11:52.169 --> 00:11:55.570 usually take the vastus lateralis muscle. Excellent. 00:11:55.649 --> 00:11:58.590 So after all that ordeal, you had the samples, 00:11:58.710 --> 00:12:01.889 you processed them. And then let's talk about 00:12:01.889 --> 00:12:03.970 the outcome measures. So what you were comparing 00:12:03.970 --> 00:12:06.289 and what you were measuring and then comparing 00:12:06.289 --> 00:12:09.529 in the study. Yeah. Yeah. So maybe one thing 00:12:09.529 --> 00:12:11.769 we didn't really cover yet, what I think is also 00:12:11.769 --> 00:12:15.039 really, really cool. of the study is the the 00:12:15.039 --> 00:12:18.840 way how we measured blood flow because usually 00:12:18.840 --> 00:12:22.000 when people measure blood flow it's often in 00:12:22.000 --> 00:12:24.860 just the big artery of the leg for example so 00:12:24.860 --> 00:12:28.039 in the artery you can just measure how many milliliters 00:12:28.039 --> 00:12:30.980 per minute of blood is is flowing through it 00:12:30.980 --> 00:12:33.559 and it's also quite easy to measure so it's being 00:12:33.559 --> 00:12:37.460 done quite often but the artery basically supplies 00:12:37.460 --> 00:12:40.720 not only the muscle but also all the other tissues 00:12:40.720 --> 00:12:45.559 like the skin connect tissue, bone, also, of 00:12:45.559 --> 00:12:48.279 course, the whole lower leg and everything. So 00:12:48.279 --> 00:12:51.299 we wanted to go one step further and measure 00:12:51.299 --> 00:12:54.899 the muscle itself. And even a little bit further 00:12:54.899 --> 00:12:58.340 than that, we only wanted to measure the very 00:12:58.340 --> 00:13:00.879 smallest blood vessels in the muscle, so the 00:13:00.879 --> 00:13:05.080 microvasculature. And the only problem then is 00:13:05.080 --> 00:13:08.059 that you cannot just pick up an ultrasound and 00:13:08.059 --> 00:13:10.539 measure it because the signal of the blood flowing 00:13:10.539 --> 00:13:13.399 through the micro... microvasculature is so low 00:13:13.399 --> 00:13:16.840 that essentially you just cannot measure it without 00:13:16.840 --> 00:13:20.419 a contrast. So that's why we had to infuse a 00:13:20.419 --> 00:13:24.120 contrast basically directly into their circulation, 00:13:24.500 --> 00:13:28.080 so in a vein. And this contrast, it sounds maybe 00:13:28.080 --> 00:13:31.039 a bit weird, but this contrast was very, very 00:13:31.039 --> 00:13:34.220 tiny micro bubbles, so kind of like very tiny 00:13:34.220 --> 00:13:37.600 gas bubbles. They were so small, they are approximately 00:13:37.600 --> 00:13:40.700 the same size as a red blood cell. So we infused 00:13:40.700 --> 00:13:43.570 them. directly into the circulation. So then 00:13:43.570 --> 00:13:45.570 they basically just go around the whole body. 00:13:45.629 --> 00:13:48.210 Because they are so small, they also go through 00:13:48.210 --> 00:13:51.269 all the tiny blood vessels. And because it's 00:13:51.269 --> 00:13:54.450 essentially a gas bubble, it reacts to the ultrasound 00:13:54.450 --> 00:13:57.669 waves, so the ultrasound signal, and it basically 00:13:57.669 --> 00:14:01.230 enhances it. So we can actually see the blood 00:14:01.230 --> 00:14:03.289 flow through the microvasculature. Well, now 00:14:03.289 --> 00:14:05.590 I have questions. Wait, wait, wait. What kind 00:14:05.590 --> 00:14:08.190 of gas did you use? There's a company, Braco, 00:14:08.409 --> 00:14:11.389 who makes these micro bubbles. And it has already 00:14:11.389 --> 00:14:14.889 been used also in just at cardiology departments 00:14:14.889 --> 00:14:18.210 to really visualize certain areas of the heart, 00:14:18.289 --> 00:14:20.029 for example, if they think there's some kind 00:14:20.029 --> 00:14:23.649 of damage. So that's basically just like a prepackaged 00:14:23.649 --> 00:14:27.070 vial with the micro bubbles in it that we would 00:14:27.070 --> 00:14:31.289 get. And then over the time of six minutes, we 00:14:31.289 --> 00:14:35.740 would then infuse it. So very slowly into the 00:14:35.740 --> 00:14:38.000 circulation. And then in the circulation, it 00:14:38.000 --> 00:14:40.759 goes around. So during those six minutes, then 00:14:40.759 --> 00:14:43.519 we can do like all the measurements that we wanted 00:14:43.519 --> 00:14:47.740 to do. You injected it to the, was it thigh vein 00:14:47.740 --> 00:14:50.259 or how did you? Yeah, no, just here in the elbow. 00:14:51.639 --> 00:14:54.320 Hey, come on. And then you inject it and in six 00:14:54.320 --> 00:14:56.120 minutes it's everywhere. The bubbles are everywhere. 00:14:56.399 --> 00:14:59.659 Oh, yeah, yeah, yeah. For sure. I think so. It 00:14:59.659 --> 00:15:01.500 also kind of depends on the heart rate, of course. 00:15:01.539 --> 00:15:04.940 So after the exercise, I would say within one 00:15:04.940 --> 00:15:07.710 minute. you could already see the bubbles appearing 00:15:07.710 --> 00:15:10.990 in the leg. But I think in rest, it takes a bit 00:15:10.990 --> 00:15:13.809 longer because you do want to have like a steady 00:15:13.809 --> 00:15:16.509 state from the micro bubbles in the circulation. 00:15:16.929 --> 00:15:20.690 So we use, in rest, we wait three minutes. So 00:15:20.690 --> 00:15:23.009 three minutes before we actually start the measurements. 00:15:23.250 --> 00:15:25.970 And how much time do you have until the, are 00:15:25.970 --> 00:15:28.929 they cleared? Are we, how did they get? Yeah, 00:15:28.970 --> 00:15:30.789 that's also quite interesting. So because they 00:15:30.789 --> 00:15:33.450 are just gas bubbles, you breathe them out. So 00:15:33.450 --> 00:15:36.730 when, after the six minutes, We stopped the infusion 00:15:36.730 --> 00:15:39.570 and then actually already after 10 minutes, there's 00:15:39.570 --> 00:15:42.110 like barely any bubbles left in the system because 00:15:42.110 --> 00:15:45.009 every time they pass the lungs, you just breathe 00:15:45.009 --> 00:15:47.789 them out. Can you, can you smell that? No, no, 00:15:47.870 --> 00:15:50.169 no, you can't smell it. No, that would be funny. 00:15:50.350 --> 00:15:53.750 Like, ooh. Yeah. But I think also the, another 00:15:53.750 --> 00:15:55.950 cool aspect from this study and this measurement 00:15:55.950 --> 00:15:58.490 was that we had two of the ultrasound machines, 00:15:58.750 --> 00:16:02.950 so we could measure it in both legs at exactly 00:16:02.950 --> 00:16:05.539 the same time. then we could just infuse the 00:16:05.539 --> 00:16:08.360 micro bubbles and then at exactly the same time 00:16:08.360 --> 00:16:11.299 we could see how many of those bubbles were passing 00:16:11.299 --> 00:16:15.299 through both legs so you did that you did exercise 00:16:15.299 --> 00:16:18.240 then you did the cooling protocol did you check 00:16:18.240 --> 00:16:21.279 again how the so did you inject them twice no 00:16:21.279 --> 00:16:24.799 we we injected them five times yeah tell me so 00:16:24.799 --> 00:16:28.539 we did it at rest at the beginning after exercise 00:16:28.539 --> 00:16:31.740 after the the cooling and then two more times 00:16:31.740 --> 00:16:34.179 during the recovery so what was actually also 00:16:34.179 --> 00:16:37.159 cool is so we did some pilot testing and with 00:16:37.159 --> 00:16:39.480 the with the pilot testing so before we would 00:16:39.480 --> 00:16:41.919 actually we were doing the study we did some 00:16:41.919 --> 00:16:45.100 we already did it with the two machines and we 00:16:45.100 --> 00:16:48.080 had a person with one leg having the the ice 00:16:48.080 --> 00:16:50.500 bath and then afterwards you could already see 00:16:50.500 --> 00:16:53.379 on the screen well while we were doing the measurements 00:16:53.379 --> 00:16:57.120 that there was like oh Almost no of the bubbles. 00:16:57.690 --> 00:17:02.129 in the cooled leg versus the control leg. So 00:17:02.129 --> 00:17:05.269 already at that point, we were like, wow, okay, 00:17:05.450 --> 00:17:09.349 there seems to be something going on here. And 00:17:09.349 --> 00:17:11.509 I think we can also see that, of course, now 00:17:11.509 --> 00:17:14.950 when we did all the 12 participants, you can 00:17:14.950 --> 00:17:19.470 see like a 60 to 70 % reduction in the blood 00:17:19.470 --> 00:17:21.950 flow in the muscle after the cooling, which I 00:17:21.950 --> 00:17:24.569 think is a really large effect. Wow. The main 00:17:24.569 --> 00:17:27.589 finding is that after cool... cooling the leg 00:17:27.589 --> 00:17:31.970 that was cooled had reduced blood flow through 00:17:31.970 --> 00:17:36.190 capillaries to this leg. in mind is it possible 00:17:36.190 --> 00:17:41.190 yes or no and why that this would actually elicit 00:17:41.190 --> 00:17:44.589 bigger adaptation later because it would be more 00:17:44.589 --> 00:17:47.630 stressful on the leg after so exercise is one 00:17:47.630 --> 00:17:50.170 stress what should happen is the stress then 00:17:50.170 --> 00:17:53.069 there is a recovery so kind of dipping with exercise 00:17:53.069 --> 00:17:56.549 and then we hope for super compensations would 00:17:56.549 --> 00:18:00.490 cooling be adding a stress so you drop exercise 00:18:00.490 --> 00:18:02.670 then you drop lower and then you're building 00:18:02.670 --> 00:18:07.200 maybe this Yeah, so that is actually also something 00:18:07.200 --> 00:18:10.559 that someone once told me. That they thought 00:18:10.559 --> 00:18:14.160 that maybe cooling would reduce blood flow. But 00:18:14.160 --> 00:18:17.200 then only for a little bit or for a short period 00:18:17.200 --> 00:18:20.700 of time. And then it would like shoot up. But 00:18:20.700 --> 00:18:22.900 that's actually not what we saw at all. Because 00:18:22.900 --> 00:18:26.339 after the cooling, it went straight down. And 00:18:26.339 --> 00:18:29.480 then one hour after, it was still down. And then 00:18:29.480 --> 00:18:33.289 even three hours after, it was still. like a 00:18:33.289 --> 00:18:37.430 little bit down. So it looks like it just reduces. 00:18:37.589 --> 00:18:40.809 And then while the muscle is basically just heating 00:18:40.809 --> 00:18:44.230 up again, it also, you see the blood flow kind 00:18:44.230 --> 00:18:47.250 of returning back to baseline. We don't, of course, 00:18:47.269 --> 00:18:50.269 know what happens after the three hours, four 00:18:50.269 --> 00:18:54.789 hours, but I would be surprised if somehow it 00:18:54.789 --> 00:18:58.410 shoots up. It seems to be mostly related to just 00:18:58.410 --> 00:19:02.400 the reduction in the muscle temperature. That's 00:19:02.400 --> 00:19:06.460 what I think at least. All right. 60, 70%. That's 00:19:06.460 --> 00:19:10.259 shocking. So how it's possible that some athletes 00:19:10.259 --> 00:19:13.160 are swearing that it makes them recover faster 00:19:13.160 --> 00:19:16.680 and makes them better athletes? Yeah, so there 00:19:16.680 --> 00:19:19.359 is a bit of a difference in the context. So, 00:19:19.400 --> 00:19:23.279 for example, cold kind of like an analgesic effect, 00:19:23.440 --> 00:19:26.180 so it can reduce pain. So and because of that, 00:19:26.339 --> 00:19:30.240 it also has quite a strong placebo effect, probably. 00:19:30.420 --> 00:19:33.480 So if you look at, for example, next day performance, 00:19:33.779 --> 00:19:37.279 quite often you can see indeed sometimes. a bit 00:19:37.279 --> 00:19:40.400 of a better performance but that increase in 00:19:40.400 --> 00:19:43.420 performance doesn't really seems to be very different 00:19:43.420 --> 00:19:47.220 than just normal placebo effect so it's a bit 00:19:47.220 --> 00:19:49.880 difficult to really say whether it's really the 00:19:49.880 --> 00:19:53.460 the cooling that has any beneficial effects on 00:19:53.460 --> 00:19:56.720 let's say next day performance or it's just because 00:19:56.720 --> 00:19:58.940 they think they will have better performance 00:19:58.940 --> 00:20:01.759 they you go into the into the ice bath and you 00:20:01.759 --> 00:20:05.200 think okay this will help my recovery and tomorrow 00:20:05.200 --> 00:20:07.980 i can deliver or better, I can perform better. 00:20:08.160 --> 00:20:11.240 Yeah, it's difficult to really say that. Any 00:20:11.240 --> 00:20:15.579 other, so you observed the less bubbles in the 00:20:15.579 --> 00:20:19.099 cooled leg up to four hours after, still less 00:20:19.099 --> 00:20:22.759 bubbles. So with the exercised leg, the blood 00:20:22.759 --> 00:20:26.279 flow increased after exercise, I assume, then 00:20:26.279 --> 00:20:29.720 the cooled leg would have the drop in the bubbles, 00:20:29.819 --> 00:20:33.579 how the non -cooled leg would behave. That's 00:20:33.579 --> 00:20:36.049 also one thing that we were really... happy with. 00:20:36.150 --> 00:20:38.390 We were measuring, of course, blood flow in both 00:20:38.390 --> 00:20:42.490 legs at rest and after exercise without any intervention 00:20:42.490 --> 00:20:45.750 yet. And those values actually were pretty much 00:20:45.750 --> 00:20:48.109 identical, which is of course what you would 00:20:48.109 --> 00:20:51.230 hope, but you never know. So in both legs, you 00:20:51.230 --> 00:20:54.930 saw a very large increase in blood flow and it 00:20:54.930 --> 00:20:58.049 was like exactly the same. for uh for each leg 00:20:58.049 --> 00:21:01.130 and then after the cooling you saw that the control 00:21:01.130 --> 00:21:04.910 leg was still a bit elevated compared to rest 00:21:04.910 --> 00:21:07.869 so of course it goes down after exercise but 00:21:07.869 --> 00:21:10.869 it was still slightly elevated and the cold leg 00:21:10.869 --> 00:21:14.470 was already actually uh i believe below resting 00:21:14.470 --> 00:21:17.109 values there was quite a quite a substantial 00:21:17.109 --> 00:21:19.930 drop did it happen for everyone or there were 00:21:19.930 --> 00:21:22.809 some cases that that we had differently yeah 00:21:22.809 --> 00:21:25.470 that's uh that's also a different point or an 00:21:25.470 --> 00:21:28.759 interesting point There were, I think, 2 out 00:21:28.759 --> 00:21:33.759 of 12. that didn't really show much of an effect. 00:21:33.960 --> 00:21:37.460 So I would say 10 clearly showed an effect and 00:21:37.460 --> 00:21:41.160 then two, like not really. Of course, you always 00:21:41.160 --> 00:21:45.220 have some variation in your measurement. So that's 00:21:45.220 --> 00:21:47.619 why we, of course, test groups and not only one 00:21:47.619 --> 00:21:50.160 person. So you cannot really say too much about 00:21:50.160 --> 00:21:52.799 it. But still, what was also interesting is that 00:21:52.799 --> 00:21:56.700 those two people, if you looked at the incorporation 00:21:56.700 --> 00:22:00.299 of the amino acid tracer into the... muscle also 00:22:00.299 --> 00:22:03.420 in their muscle you couldn't really see a large 00:22:03.420 --> 00:22:06.720 difference and in those other 10 you could so 00:22:07.230 --> 00:22:10.390 It definitely seems that there's quite a good 00:22:10.390 --> 00:22:14.250 relationship between the changes in blood flow 00:22:14.250 --> 00:22:18.250 and then because of that, also how nutrients 00:22:18.250 --> 00:22:21.970 from the diet actually get into the muscle. And 00:22:21.970 --> 00:22:24.250 of course, it makes sense if you say it, but 00:22:24.250 --> 00:22:28.250 it's still good to actually see that back in 00:22:28.250 --> 00:22:30.569 the data, especially with actually a relatively 00:22:30.569 --> 00:22:33.609 small sample size. All right, so let's go there. 00:22:33.690 --> 00:22:37.279 So we covered to rest, exercise. checking the 00:22:37.279 --> 00:22:42.039 the blood flow after cooling and then we didn't 00:22:42.039 --> 00:22:45.799 even talk too much about how the traces traveled 00:22:45.799 --> 00:22:47.859 through the body and what have you found there 00:22:47.859 --> 00:22:51.839 um could you move us through that yeah yeah so 00:22:51.839 --> 00:22:56.059 that was so right after the cooling we had the 00:22:56.059 --> 00:22:59.319 uh the drink which was essentially just a recovery 00:22:59.319 --> 00:23:02.740 drink. So it was basically a protein shake that 00:23:02.740 --> 00:23:05.720 also had some carbohydrates in it. But then we 00:23:05.720 --> 00:23:09.519 also added the, let's say, the special amino 00:23:09.519 --> 00:23:13.420 acid. So we call it the amino acid tracer. So 00:23:13.420 --> 00:23:16.980 it basically behaves like a normal amino acid, 00:23:17.059 --> 00:23:21.380 but we can find it back in the body. So they 00:23:21.380 --> 00:23:25.130 drank. the drink and then you can also see that 00:23:25.130 --> 00:23:29.309 the the amino acid tracer was like clearly went 00:23:29.309 --> 00:23:32.390 into the circulation because we took quite some 00:23:32.390 --> 00:23:35.990 blood samples and then also throughout the the 00:23:35.990 --> 00:23:39.109 whole recovery phase you could see that this 00:23:39.109 --> 00:23:42.049 tracer was essentially just going through the 00:23:42.049 --> 00:23:45.019 circulation And then because at the very end 00:23:45.019 --> 00:23:48.220 of the day, we took the muscle biopsy from both 00:23:48.220 --> 00:23:51.119 legs, then we could see that in the cooled leg, 00:23:51.299 --> 00:23:56.339 there was 30 % less of the tracer built into 00:23:56.339 --> 00:23:59.779 the muscle compared to the control leg. Wow. 00:23:59.940 --> 00:24:03.779 So how do you see the tracer? Is it glowing? 00:24:04.420 --> 00:24:08.339 No, no. It's actually, it's basically just a... 00:24:08.730 --> 00:24:12.789 The carbon atoms. So you have an amino acid. 00:24:12.890 --> 00:24:16.009 It has basically like a whole structure made 00:24:16.009 --> 00:24:19.490 of carbon atoms. And maybe if people remember 00:24:19.490 --> 00:24:22.990 from back in the day, like chemistry, you would 00:24:22.990 --> 00:24:25.529 have like all the C's, right? And you have like 00:24:25.529 --> 00:24:29.269 H's and CO, whatever, like a whole structure 00:24:29.269 --> 00:24:32.250 of a molecule. The amino acid tracer is essentially 00:24:32.250 --> 00:24:35.150 just exactly the same as a normal amino acid, 00:24:35.329 --> 00:24:38.609 but just the carbon atoms, so the Cs, they are 00:24:38.609 --> 00:24:41.950 slightly heavier. So they have an additional 00:24:41.950 --> 00:24:45.690 neutron. So basically it's not 12 carbon, but 00:24:45.690 --> 00:24:48.569 it's 13 carbon. So technically it's slightly 00:24:48.569 --> 00:24:52.970 heavier, but it still just acts normally like 00:24:52.970 --> 00:24:56.849 a normal amino acid. But because it has those 00:24:56.849 --> 00:25:00.529 heavier carbon atoms, we can... detect those 00:25:01.119 --> 00:25:04.859 using all kinds of machines like very technical 00:25:04.859 --> 00:25:08.259 machines and we can then see how much of that 00:25:08.259 --> 00:25:11.859 yeah of the tracer is then back or then in this 00:25:11.859 --> 00:25:14.180 case in the muscle or in the blood so you have 00:25:14.180 --> 00:25:18.059 like the spike for c12 here and for 13 it will 00:25:18.059 --> 00:25:21.299 be just slightly off yeah exactly yeah yeah all 00:25:21.299 --> 00:25:23.839 right wow all right so that like there is no 00:25:23.839 --> 00:25:27.480 no guessing here it's you saw it it's it's for 00:25:27.480 --> 00:25:31.440 sure so you found two things one was blood supply 00:25:31.440 --> 00:25:35.460 was very different, 60 -70 % difference of blood 00:25:35.460 --> 00:25:39.519 supply between the cold leg and the hormone -neutral 00:25:39.519 --> 00:25:44.500 leg, and 30 % difference in the special amino 00:25:44.500 --> 00:25:48.240 acids bound into the muscle after you provided 00:25:48.240 --> 00:25:50.740 the tracer. Yeah, exactly, yeah. And then also 00:25:50.740 --> 00:25:52.680 one of the things that we saw was that there 00:25:52.680 --> 00:25:55.160 was quite a good correlation between the two. 00:25:55.259 --> 00:25:58.099 So like what I said about the two... participants 00:25:58.099 --> 00:26:01.039 that didn't really respond in both. You could 00:26:01.039 --> 00:26:03.579 definitely see a pattern that the people who 00:26:03.579 --> 00:26:08.119 would, let's say, have the largest negative effect 00:26:08.119 --> 00:26:11.579 of the cooling in terms of blood flow also had 00:26:11.579 --> 00:26:14.759 the largest negative effect in the amino acids 00:26:14.759 --> 00:26:17.559 incorporation into the muscle. Now, from your 00:26:17.559 --> 00:26:20.519 expert to all the coaches and athletes, how would 00:26:20.519 --> 00:26:23.339 you sum up the results of your study? What does 00:26:23.339 --> 00:26:27.049 it mean for an athlete and a coach? So I would 00:26:27.049 --> 00:26:31.170 be very careful with using cold water immersion, 00:26:31.390 --> 00:26:35.690 especially during training phases where either 00:26:35.690 --> 00:26:39.609 muscle growth or the gain in muscle strength 00:26:39.609 --> 00:26:42.769 is important. I would say in those situations, 00:26:42.890 --> 00:26:46.690 I would just not. do it or if you really want 00:26:46.690 --> 00:26:50.509 to do it do it as far away from your exercise 00:26:50.509 --> 00:26:53.529 as possible because yeah what we did now was 00:26:53.529 --> 00:26:56.509 of course first the exercise and then immediately 00:26:56.509 --> 00:26:58.930 after into the ice bath so of course it could 00:26:58.930 --> 00:27:02.289 be that possible negative effects are much much 00:27:02.289 --> 00:27:06.490 less if you just split split them up more yeah 00:27:06.490 --> 00:27:10.150 and I think for some it can still be useful during 00:27:10.150 --> 00:27:14.049 let's say competitions so if you have multiple 00:27:14.220 --> 00:27:17.579 multiple competitions per day or a couple days 00:27:17.579 --> 00:27:20.700 in a row. Yeah, on one hand, it could help for 00:27:20.700 --> 00:27:24.490 some. But on the other hand, yeah, is it really 00:27:24.490 --> 00:27:29.490 helping more than just a placebo effect? I think 00:27:29.490 --> 00:27:32.470 that's the main thing where I'm still struggling 00:27:32.470 --> 00:27:35.910 with is, yeah, still should people do it during 00:27:35.910 --> 00:27:39.049 competition? I think that's still an area that 00:27:39.049 --> 00:27:42.450 we can't really say at the moment. Because I 00:27:42.450 --> 00:27:45.410 think in this case, in the study that we did, 00:27:45.569 --> 00:27:48.890 the focus was more on muscle adaptation. And 00:27:48.890 --> 00:27:51.230 I think if you look at performance, recovery 00:27:51.230 --> 00:27:55.829 so let's say you had a an intense match and you 00:27:55.829 --> 00:27:59.049 want to or a competition and the next day Again, 00:27:59.230 --> 00:28:01.990 you need to perform. I think that's a very different 00:28:01.990 --> 00:28:05.029 question than what we looked at in this study. 00:28:05.230 --> 00:28:08.329 Also, there's an aspect of exercising in heat 00:28:08.329 --> 00:28:11.809 or hot environment. Then we have to balance cooling 00:28:11.809 --> 00:28:15.130 down, like literally dropping the body temperature 00:28:15.130 --> 00:28:19.549 down, matching the sun for two hours in a tournament 00:28:19.549 --> 00:28:21.869 that takes four days and so on. So there are 00:28:21.869 --> 00:28:26.210 still some benefits we have to kind of keep. 00:28:26.619 --> 00:28:30.299 the context in mind exactly yeah i agree yeah 00:28:30.299 --> 00:28:32.720 awesome two more questions to finish the first 00:28:32.720 --> 00:28:36.079 one is what is your favorite exercise yeah actually 00:28:36.079 --> 00:28:40.140 i i did do quite some olympic weightlifting for 00:28:40.140 --> 00:28:43.180 some time and i must say i really like the power 00:28:43.180 --> 00:28:47.740 clean because it's just like just raw power just 00:28:47.740 --> 00:28:51.150 like Pulling on something full force is just 00:28:51.150 --> 00:28:54.210 a good feeling, I think. So yeah, I would definitely 00:28:54.210 --> 00:28:57.750 say that the Power Queen is my favorite. All 00:28:57.750 --> 00:28:59.789 right. And the last question is where people 00:28:59.789 --> 00:29:02.650 can find you if they want to follow your research 00:29:02.650 --> 00:29:07.809 or ask a question. Yeah. So research, I try to 00:29:07.809 --> 00:29:12.309 kind of share on all kinds of platforms. So X. 00:29:12.960 --> 00:29:17.019 Our Twitter, that's one. Also LinkedIn, of course. 00:29:17.160 --> 00:29:22.339 But also on my Instagram, I post about my research 00:29:22.339 --> 00:29:26.279 sometimes. So my handle is basically always just 00:29:26.279 --> 00:29:30.799 my name, but with W in between. So it's Milan 00:29:30.799 --> 00:29:35.400 W Betts. And yeah, with that handle, I think 00:29:35.400 --> 00:29:38.759 you could find me on several platforms. All right, 00:29:38.779 --> 00:29:40.839 Milan. Thank you so much for today. I learned 00:29:40.839 --> 00:29:43.859 a lot. I hope that... The audience will enjoy 00:29:43.859 --> 00:29:46.000 too. I hope so too. Thanks for having me.