#089 Why Exercise Intensity Matters for Longevity | CrossFit for Health 2024

Optimal sauna parameters, infrared vs. Finnish, and why hot baths also work

Rhonda covers the most robust sauna protocols for health, how infrared compares to traditional Finnish saunas, and why hot baths can be a valid.

"That's my disclosure. So focusing on exercise, it's going to be really vigorous exercise. We're going to talk about the importance of vigorous intensity exercise going like 80 percent max heart rate or more. We're going to talk about the brain benefits. We're going to talk about cardiovascular benefits, cancer a little bit, exercise snacks, then we're going to get into some muscle biology a little bit, the importance of protein, resistance training, and then into deliberate heat exposure and sauna and how that can synergize with both exercise and also with resistance training."

Going from below-average to normal VO2max adds ~2 years of life expectancy

The largest mortality benefit comes from moving out of the lowest VO2max tier.

"What type of aerobic exercise? I think it's pretty clear that high intensity interval training is one of the best ways to improve your VOT max. And particularly when you do longer intervals, yes, you can improve your your cardiorespiratory fitness with any type of aerobic exercise, particularly if you're starting from being sedentary and then going up, right. But there was a really important study that was published, a large, large population of people that showed people that are doing moderate intensity sort of zone two like training, you know, this is the kind of exercise that is more enjoyable, you can go for a run, and you can still have somewhat of a conversation, you're breathy. Those people are doing two and a half hours per week, they're meeting the guidelines. And yet they couldn't improve their VO2 max, about 40% of those people. So you're talking like half the population here until they added in some high intensity interval training."

Levine study: 2 years of vigorous exercise reversed heart stiffening in sedentary adults

Sedentary 50-year-olds who did 4-5 hours/week of aerobic exercise with vigorous intensity reversed cardiac stiffening, while the stretching control.

"They put them on one or two different exercise protocols. The other group did a high intensity, vigorous exercise workout program. And this was a two-year intervention study."

Lighter weights build as much muscle as heavy if effort is high enough

Research from Stu Phillips and Brad Schoenfeld shows you can lift lighter weights and gain equivalent muscle mass and strength as long as you train.

"There's been a lot of animal studies on this. But there's now been some human data where people, you know, there's intervention trials where they're, you know, they basically immobilize one of their limbs for a period of weeks and then did some local heat exposure. And the local heat exposure prevented the disuse atrophy by like 40%. So, you know, I think that's a very relative, again, a very relevant weight for people that are injured or again, people that are older and they're experiencing a lot of muscle atrophy as well but there was also a very recent study and this is small so it needs to be repeated but people that were engaging in resistance training either just alone or then went into the sauna right after the resistance training they had greater gains in muscle mass if they went to sauna right after the resistance training compared to resistance training well they actually actually, it was biomarkers of it. So they didn't directly measure muscle mass. It was biomarkers. But anyways, I think it's an encouraging and promising area that, of course, I'm excited about and glad people are out there researching. But it's another possibility for a synergy between resistance training, between vigorous intensity exercise, your exercise program and then engaging in deliberate heat exposure as well so what are the parameters in a lot of these studies well a lot of the parameters in many of these studies are coming out of Finland the temperature is about 174 degrees Fahrenheit and the duration spent in the sauna is about 20 minutes and that's important because people that spent less than 20 minutes, like let's say they were in there for 11 minutes, they didn't have the robust effects."

Sauna mimics moderate cardio: comparable heart rate, blood pressure, and stroke volume effects

Sauna produces responses similar to moderate exercise: heart rate ~120 bpm, increased plasma volume, and cardiovascular benefits.

"And it's really like the studies have shown they're pretty comparable. So like when you're doing the activity, heart rate goes up, your blood pressure goes up while you're doing the activity, but then after the activity, whether it's exercise or sauna, you're getting blood pressure improvements, your resting heart rate is improved, and so these things are comparable. So really in some way, I would say engaging in deliberate heat exposure from the sauna is mimicking moderate intensity aerobic exercise. And there have been observational studies and some intervention studies we'll talk about in a second, but observational studies looking at people that are, and this is in Finland where saunas are pretty ubiquitous and most people are using them. So people in Finland that have sauna or using sauna and they exercise have a better cardiorespiratory fitness than people that exercise alone. And we're talking about the same volume of exercise. And these people are the ones that do that, but also sauna had a better cardiorespiratory fitness than people that only engaged in exercise."

Extreme endurance training and coronary calcification: risk is still lower overall

Elite endurance athletes may show slightly higher coronary calcification, but their overall cardiovascular death risk remains lower than committed.

"And I'm gonna defer to some of the experts on that where like Dr. Ben Levine, I think he, as far as I've heard from him is yes, like when you get to this like elite, elite athlete, endurance athlete level, I mean, there's some of the increased risks to do with like coronary calcification, whatever the, you know, the increased risks of that outcome are actually even lower, even if the coronary calcification is a little bit higher."

Finnish vs. infrared sauna and whether temperatures above 200F help or hurt

Both sauna types work by raising core temperature and heart rate. Finnish saunas 4-7x/week at 174F show 66% reduced dementia risk.

"Those are great questions. All right. So to first address the mechanisms and is the beneficial effect of deliberate heat exposure that I've talked about today due to the increased heart rate, you know, the mimicking of, I would say, moderate intensity exercise. I think a lot of it comes down to that, the improvements in respiratory fitness and cardiovascular improvements, also the heat shock proteins as well. So the heat shock proteins are playing a role in the muscle, they're playing a role in the immune system, and they're also playing a role in the brain. So people that use finish saunas four to seven times a week at those temperature you know parameters that i mentioned have about a 66 reduction dementia risk um Alzheimer's disease risk so yeah i do think there is it really does come down to elevating the core body temperature and getting that heart rate up and and being being physically uncomfortable like you are when you're exercising um infraredrared saunas do work a little bit different. They're moving molecules in your body and heating you up a different way. There is evidence coming out of Dr. Ashley Mason's lab at UCSF, who I've been collaborating with, showing that a very rigorous infrared sauna protocol, it's like a heat bed where you head out."