Ep. 24 – Research Shorts: High Intensity Exercise, Delayed Onset Muscle Soreness, and the Microbiome and Exercise
On this episode of Straight Talk on Health, Dr. Chet Zelasko takes a look at three recently published papers on short bursts of high intensity exercise, Delayed Onset Muscle Soreness, and how exercise may increase the desire to exercise by changes in the microbiome.
Welcome to Straight Talk on Health, I’m your host Dr. Chet Zelasko. Together with WGVU in Grand Rapids MI, I examine the world of health research and news. Whether it’s research that makes the news, another miracle diet, a new food fad or an exercise trend, I look at the science behind them, and let you know whether it’s real or not. You can check out other things that I do on my website Drchet.com and sign up for my free emails.
High-intensity interval training (HIIT) has become very popular due to the possibility of gaining fitness in a short amount of time, but when done correctly workouts still take 20 to 40 minutes. A group of researchers examined the United Kingdom Biobank data to see if a sub-group of subjects who wore accelerometers might benefit from short bouts (one or two minutes) of intense physical activity independent of a regular exercise program. Researchers termed the exercise bouts “vigorous intermittent lifestyle physical activity” (VILPA) and they were not part of an intentional exercise program. They just happened with people who were going about their daily routines.
They tracked the subjects for almost seven years to see if there was any reduction in their death rate. The data showed that as few as two or three short bouts or approximately three to four minutes of VILPA per day were associated with substantially lower all-cause, cardiovascular, and cancer mortality risk. More VILPA sessions per day resulted in a greater reduction, but the greatest reduction occurred in three to four minutes per day. The reduction was a 38% to 40% reduction in all-cause and cancer mortality risk and a 48% to 49% reduction in CVD mortality risk. One more thing: the average age of the over 25,000 subjects was 61.8 years.
The facts that struck me was whether a person exercised or not, or ate a high amount of vegetables and fruit or not, they had a reduction in mortality. To be safe, you and your doctor should discuss whether you can try a minute or two of intense physical activity a few times per day. Maybe it will happen organically as part of your day, like sprinting up a flight of stairs to get to a meeting, or running to catch a bus, or chasing a toddler. Or maybe that exercise bike you’ve been using as a clothing rack can be put to use as it was intended. Riley and the bus stop story. Then, attacking all hills. Find your spots and do what you can. You may have years to gain.
Delayed-Onset Muscle Soreness (DOMS) is common in sedentary people who overdo it such as weekend warriors. Ever help someone move? Ever move 5 yards of landscape mulch and spread it around the yard? Ever play in a basketball tournament once a year? So you know what DOMS is. Researchers wanted to test what benefits these occasional exercisers may get from eating almonds compared to cereal bar.
Researchers recruited a group of sedentary volunteers between the ages of 30-65 years old. They wanted to examine the effects of 2 oz of almond intake every day for 4 weeks on measures of pro-inflammatory hormones and oxylipins. Oxylipins are oxidized fats that can have pro- or anti-inflammatory effects. The control group ate a cereal bar with the same caloric content.
After 28 days, all subjects performed a 90-minute workout session designed to damage muscle that included a bout of maximal aerobic exercise on an exercise bike, weight training, jumping, and other activities. They succeeded based on the blood levels of enzymes indicating DOMS as well as standardized questionnaires assessing pain post exercise. The subjects that ate almonds every day had more anti-inflammatory oxylipins post exercise while the controls had an increase in pro-inflammatory oxylipins. Most importantly, the almond eaters appeared to recover a little faster.
Almond skins are a treasure of phenolic compounds. While this was a small study (69 total subjects), there were benefits to eating almonds every day for non-exercising weekend warriors. Could other high phenolic foods have the same benefit? Time will tell. Almonds are a treasure trove of omega-3 fatty acids, fiber, protein so finding a way of snacking on them instead of some other snack may prove beneficial. How about you regular exercisers? I’m betting you’ll get some benefit as well. It’s all part of eating better. Just remember one thing: you have to take something out of your diet and replace it with the almonds as 2 oz of almonds is about 380 calories. Great calories but still have to be accounted for.
Finally it doesn't seem like any review of recent research would be complete without a study on the microbiome. There were a number of them that were published in the last month but one of them stood out to me, primarily as an exercise physiologist. Why do people exercise? What motivates them? Everybody knows that exercise is good for them yet less than 20% of the adult population exercises at a rate that really can benefit them. And that means that they're exercising for 30 to 45 minutes four to five days a week. Now of course, people can be restricted by diseases and conditions and so they do the best that they can and that's absolutely terrific. But for those that don't have limitations, why do they hit the snooze button instead of getting up and going for a walk? Why do they stop at the bar instead of the gym? Well it looks like a group of researchers may have found something that seems to be related to the gut brain access. And that's spelled AXIS. In other words the connection between the microbiome and the brain.
Let me tell you a little bit about what they found. Not exactly how they did it because believe me it was complicated. But what they found. The researchers found that two bacterial species closely tied to better exercise performance in exercising mice, Eubacterium rectale and Coprococcus eutactus. These bacteria are found in higher amounts in exercising rodents as a result of exercising. They produce metabolites known as fatty acid amides (FAAs). Not to be confused with SCFA which are beneficial to exercise. Rather, these chemicals stimulate receptors called CB1 endocannabinoid receptors on gut-embedded sensory nerves, which connect to the brain via the spine. The stimulation of these CB1 receptor-studded nerves causes an increase in levels of the neurotransmitter dopamine during exercise, in a brain region called the ventral striatum.
Get this. The striatum is a critical node in the brain’s reward and motivation network. The researchers concluded that the extra dopamine in this region during exercise boosts performance by reinforcing the desire to exercise. It becomes a feedback loop. One of the researchers said in an interview “This gut-to-brain motivation pathway might have evolved to connect nutrient availability and the state of the gut bacterial population to the readiness to engage in prolonged physical activity.”
There is a lot more to learn before we can say that this happens in humans. We have to actually test for that but what rodent research does, is give us a place to look and that is exactly where these researchers are going to look. But it's a whole lot more complicated than that. Is there a genetic factor involved? Is there an environmental issue that contributes to the proper bacteria being present? What role does diet have to play because ultimately, that's where the bacteria will come from. Are the bacteria there all the time already and the exercise stimulates it? And what could it do for those people that are classically sedentary? Most of the time, researchers think in terms of pharmaceuticals that may be able to stimulate the proper receptors. Or it could be putting the proper bacteria that they discovered in a supplement to the diet. But the exciting thing is that there is a connection between exercise and then wanting to exercise. It all starts with walking out that front door the very first time and starting the process for the individual.
Vigorous Intermittent Lifestyle Physical Activity: Nature Medicine. 2022; 28 (12):2521–2529
DOMS - Front. Nutr. 9:1042719. doi:10.3389/fnut.2022.1042719
Exercise and the Microbiome - “A microbiome-dependent gut–brain pathway regulates motivation for exercise” Nature 14 December 2022.