The Rundown

Muscle Power & Aging. Power is a good predictor of how you’ll handle the typical activities of daily life as you age (think climbing stairs and lifting yourself out of a chair). The problem is that declining muscle power is a hallmark of aging in your 40s and beyond and scientists don’t know for certain why it happens. A new study highlighted by Outside magazine’s Alex Hutchinson and published in the Journal of Applied Physiology investigates the mystery.

As Hutchinson explains, muscle power is the combination of how much force we can exert and how quickly we can exert it. To jump onto a box or get off the couch, we need to deliver force explosively, not gradually. Research has found that power is a more important predictor than strength for how older people are able to navigate life’s daily activities.

Power however, starts declining earlier than strength. A typical estimate is that we lose 0.5 to 1 percent of our muscle mass per year past the age of 40, with strength generally following a similar patter. Muscle power drops by 2 to 4 percent per year.

For the new study, researchers at Marquette University tested three groups: young adults with an average age of 23, older adults with an average age of 70 and a group of very old adults with an average age of 86. The tests measured the maximum power the participants could produce with their quadriceps, sitting with a bent knee then trying to straighten it as powerfully as they could. The scientists used magnetic brain stimulation and electrical stimulation of the muscles to determine how much the brain and nervous system contributed compared to the muscles themselves.

The results found, unsurprisingly, that we lose muscle power with age and the decline in power is more than the decline in strength. But, there were no appreciable declines in the brain and nervous system’s ability to signal for a powerful contraction. Rather, it was the muscles that didn’t contract as powerfully as they used to. The researchers suggest that the most likely reason for this is we tend to lose fast-twitch muscle fibers quicker than slow-twitch fibers, which leaves us with weaker and less explosive muscles in general.

So what can you do about declining muscle power? Hutchinson has a few suggestions. He notes that if you want to keep as much explosive power as you can, you need to train in explosive ways and one approach is plyometric exercises like box jumps and bounding. Another option is resistance training with lighter weights (about 60 percent of one-rep max), focusing on doing the movement as quickly as possible.

For keeping your fast-twitch muscle fibers, there may also be a case for heavy resistance training, with sets of six or less reps. If the weight is appropriately heavy, you’ll need to use your fast-twitch fibers to lift it.

It’s not yet clear which of these approaches is the most effective but it’s worth remembering that power is force times velocity, so increasing the force you’re able to deliver is a key part of the process.

Brain Boost. A new study has found that the short-term boost your brain gets after you exercise lasts throughout the following day. On average, people age 50 to 83 who did more moderate to vigorous physical activity than usual on a given day performed better in memory tests the day after.

The University College London research team looked at data from 76 men and women who wore activity trackers for eight days and took cognitive tests each day. They also quantified sleep duration and time spent in REM sleep and deeper slow-wave sleep. The team adjusted for a wide variety of factors, including the amount of moderate to vigorous physical activity the participants did on the day of the cognitive tests. They also accounted for the volunteers’ average levels of activity and sleep across the eight days they were tracked.

In addition to the brain boost from moderate to vigorous physical activity compared to a person’s average, the team found that six hours or more of sleep were also linked to better scores in memory tests the next day. More deep sleep also contributed to memory function and the study found that this accounted for a small portion of the link between exercise and improved next-day memory.

One limitation to note is that the participants were a cognitively healthy group, so the results might not be true of people who have neurocognitive disorders.

Dark Chocolate for the Win. I don’t typically highlight nutrition studies in Fit Cult, but I’m making an exception for this one since it’s possible that your (ok, my) chocolate consumption is higher than normal around the holidays. Turns out, that may not be a negative.

A new analysis out of the Harvard T.H. Chan School of Public Health says five serves of dark chocolate a week could reduce your risk of type 2 dibetes by 21 percent compared to those who abstained completely or rarely indulged.

For the study, U.S. and Chinese scientists assessed questionnaires answered by more than 100,000 female nurses and male healthcare professionals selected from the Nurses’ Health Study (1986-2018), Nurses’ Health Study II (1991-2021) and Health Professionals Follow-Up Study (1986-2020). They excluded anyone with diabetes, cardiovascular disease or cancer at baseline, unusually high or low energy intake and bodyweight changes. They also adjusted for risk factors associated with lifestyle and diet and looked at data spanning a quarter of a century.

In the initial analysis, the team found that of the participants who ate any kind of chocolate, their risk of developing type 2 diabetes was roughly 10 percent lower than that of non-chocolate eaters. In the secondary analysis, the researchers found that for those who said they ate dark chocolate versus other kinds of milk blends, the health benefits swung towards the dark-chocolate cohort. There was no discernible advantage to eating just milk chocolate.

While the researchers pooled data from previous dark chocolate studies to bolster their findings and their work shows a fairly robust association between health and dark chocolate consumption, the observational and self-reported nature of the study means there are limitations. Also, the results are not causal. Further clinical trials are needed to understand and assess the mechanisms at work.

Extra Point

Watch

Senna. This is a dramatized view of Ayrton Senna’s rise through the ranks of motor sport, produced in collaboration with his family. Thirty years after his death, it chronicles his career-defining moments from his early rivalries to his F1 journey. Senna is streaming on Netflix.

Enigma. Also on Netflix is this three episode documentary series dedicated to answering the question: Who is Aaron Rodgers? Rodgers wants viewers to draw their own conclusions as he invites cameras into his life in ways that are perhaps unprecedented for an active NFL quarterback. The series looks at Rodgers’ life on and off the field, from his season-ending injury on the fourth play of his New York Jets debut to his participation in a three-night retreat in the Costa Rican jungle where he takes the plant-based medicine, ayahuasca.

Listen

The Happiness Lab with Dr. Laurie Santos. A podcast based on Dr. Santos’ psychology course at Yale, The Happiness Lab takes listeners through the latest research on how to be happier and more fulfilled on a daily basis.

Share Fit Cult

Read

An Exercise Program for Life, Not Instagram. Steve Magness talks about how to reframe exercise so that it doesn’t feel like a sacrifice in this article from The Growth Equation.