Newsletter #219

Hey y’all, this week I thought we’d take a look at the importance of exercise frequency on morbidity and mortality. Physical activity guidelines recommend getting at least 150 minutes per week of moderate-intensity aerobic activity, or at least 75 minutes per week of vigorous-intensity aerobic activity, or an equivalent combination of the two.

It is often suggested that this activity be spread out over multiple days, but obviously for a lot of us that’s kind of hard to pull off, and indeed lack of time is one of the most commonly cited barriers to exercise. As a result, a significant number of individuals compress all of their exercise into one or two (usually consecutive) days, giving rise to the term “weekend warrior.” So the question is whether this is a viable alternative to regular training sessions distributed more evenly over an entire week.

One thing to keep in mind here is that most of the mortality benefit associated with exercise is actually achieved with a relatively modest amount. One meta-analysisof older adults found that less than 150 minutes of moderate-to-vigorous activity per week was enough to reduce mortality risk by 22%.

But if you are trying to maximize your health and lifespan, you’re probably going to have to be a bit more ambitious. A large analysis found that the optimal threshold for longevity (39% reduced all-cause mortality) occurred at somewhere between 3-5 times the amount recommended by the physical activity guidelines. That’s kind of hard to pull off in 1-2 sessions...unless you make it very intense. Recall that the guidelines state that you basically get double the benefit from one minute of vigorous exercise compared to one minute of moderate activity.

Let's take a look and see if that indeed produces the same reductions in mortality.

Researchers analyzed data from 3438 adult participants in NHANES, aged 40 and older, who wore accelerometers to objectively assess physical activity. Participants whose activity was primarily crammed into 1-2 days per week were classified as “weekend warriors.” Compared to subjects who got less than 37 minutes of moderate-to-vigorous activity per week, those who achieved greater amounts of weekly activity had a 60–69% reduced mortality rate, after adjusting for relevant covariables. Importantly, weekend warriors and those who were more frequently active experienced similar improvements in mortality.

Researchers analyzed pooled data from respondents Health Survey for England and Scottish Health Survey (n=63591), with linkage to mortality records. They divided leisure-time physical activity into four groups: 1) inactive (reporting no moderate- or vigorous-intensity activities), 2) insufficiently active (reporting <150 min/wk in moderate-intensity and <75 min/wk in vigorous-intensity activities), 3) weekend warrior (reporting ≥150 min/wk in moderate-intensity or ≥75 min/wk in vigorous-intensity activities from 1 or 2 sessions), and 4) regularly active (reporting ≥150 min/wk in moderate-intensity or ≥75 min/wk in vigorous-intensity activities from ≥3 sessions). Compared to the inactive group, all-cause mortality risk was 30% lower in the weekend warriors and 35% lower in the regularly active. Cardiovascular mortality was 41% lower in both weekend warriors and the regularly activity. One thing that jumps out at me here is that although the regularly active and weekend warrior groups both met the physical activity guidelines, the type of activity was significantly different. For example, the total amount of time spent in physical activity was 50% higher for the regularly active individuals, but the weekend warriors had a higher proportion of their time occupied by vigorous-intensity exercise. Furthermore, weekend warriors were significantly more likely to meet the guidelines through intense sporting activity; in fact, 94% of the weekend warriors reported playing sports. Key takeaway here: if you are going to try to compress all of your exercise into 1-2 sessions, it’s going to have to be pretty intense to achieve optimal benefits.

Researchers analyzed detailed data about physical activity patterns in an ongoing cohort of older men who graduated from Harvard University (n=8421). The men were classified into groups based on the amount of energy they expended in physical activity weekly. The highest category of energy expenditure, ≥1,000 calories per week, was split into two groups: “weekend warriors” who exercised 1-2 times per week, and “regularly active” whose exercise occurred at least 3 times weekly. Over the follow-up period, the regularly active men had a 36% lower risk of dying compared to the inactive participants. The weekend warriors, meanwhile, had only a 15% lower risk of death compared to the sedentary group. The researchers decided to dig a little deeper and analyzed the association between exercise and mortality rates separately among low-risk and high-risk men. High risk men had at least one risk factor: smoking, overweight, hypertension, or hypercholesterolemia. Among the low-risk men, the weekend warriors showed similar reductions in mortality to that of the regularly active subjects. But weekend warriors in the high-risk group did not show this benefit. This is probably because some of the beneficial effects of physical activity, especially on cardiometabolic markers, are relatively short-lived and need to be frequently “renewed.” For instance, exercise produces acute reductions in triglycerides, blood pressure, and insulin sensitivity that may dissipate within a day or even hours.

A little while ago, researchers had patients with insomnia randomized to sleep for four weeks at home with either a chain-weighted blanket or a light plastic chain blanket (control). 42.2% of the weighted blanket group achieved remission, compared to just 3.6% in the control group.

And when subjects were given the opportunity to use the weighted blankets for a 12-month follow-up phase, 78% managed to achieve remission from insomnia. Wow! If you have trouble sleeping, this is a pretty low-risk thing to try. This one is nice because it works year-round, with cold and warm sides.

Thanks for reading, enjoy the weekend, and we'll see y'all next week!

https://mailchi.mp/humanos.me/newsletter-219