Physical Activity - Why, When, Where, How Long, Which ?

Over the last year and a half, through a dozen odd articles, I have written how physical activity (PA) is the single most important factor in our quest to live long, healthy. In fact, PA can even overcome the downsides of poor sleep. Last week, I wrote that even if we do not have robust data regarding the health benefits of yoga, just as a form of PA (yoga as exercise), it should by extrapolation, increase our healthspan and lifespan.

While, walking is the simplest PA and any activity is better than none, there are still many questions about PA that need to be answered. Which type of PA is the best? Do I need to be active all through life? Does it matter when and where I am active?

A clutch of recent articles has tried to answer these questions.

Question 1: Who and When and How Long?

I had partly answered this in April 2022, when we looked at two studies that together told us that the earlier in life we are active, the better, any PA is better than none, and if you stop being active, you may lose its benefits over time.

A few weeks later, came another paper [1] that did a meta-analysis of the data from 9 studies totalling 33,576 people with a mean age of 62.5 years and a mean follow-up of 15.7 years. They divided the cohorts into four categories; always-inactive, always active, active over time (inactive earlier but became active) and inactive over time (active earlier but became inactive). As expected, those who were always active had a 50% reduced mortality from cardiovascular disease as compared to those who were always inactive. There was a 45% reduced mortality in those who were inactive to start with but became active later and a 20% reduced mortality in those who were active initially but then became  inactive, compared to those who were always inactive.

In short, everyone should be active, always and forever.

Question 2: Which type of exercise works best?

Another systematic review and meta-analysis of 81 controlled trials, published recently, [2] attempted to answer this question. There were 4331 participants in total. They looked at 5 patterns of exercise; continuous endurance (as in running, walking), resistance training (weights, etc), interval training (short bouts of high-intensity training), combined training (continuous endurance and resistance training on different days) and hybrid training (combination of different types of activity in a single session).

Combined training was better than all others for cardiorespiratory fitness, body composition, blood pressure control, blood sugar control and blood lipid control. Hybrid training came second.

So basically, it is best to mix up walking, running and strength training, either in different sessions through the week or in the same session. But again, if you can’t find the time to do all of this, remember, any PA is better than none and just 30-45 minutes of walking a day has huge benefits.

Question 3: Where should we be active?

It doesn’t really matter where we are physically active, whether it is outdoors or indoors, at home or in a gym, though we should avoid being outdoors on days when the AQI (air quality index) is high to reduce the harm from short and long term exposure to PM_2.5 particles.

However given that PA also helps with emotional well-being and improved cognition, the setting of the PA could make a difference in that context.

A recent study [3] randomized patients into three groups; urban walking, green walking (forest, garden) and a control group (no PA).

As intuitively expected, those who were assigned to the green walking group reported far better mental well-being scores than the other two groups.

If you have a choice between walking in a garden or forest versus walking on a treadmill or on city roads, a garden or forest is better, with the understanding that any PA anywhere is better than none.

Question 4: When during the day is the best time to be active?

This was a small study [4] of 56 exercise-trained men and women (30 women and 26 men), who were randomized to morning or evening exercise.

In women, morning exercise reduced abdominal fat and blood pressure, while evening exercise improved muscular performance. In men, evening exercise reduced blood pressure.

So, for those of you who are anyway physically active and want to move beyond just increasing your healthspan and lifespan, the time of day when you exercise may determine how your body responds to the exercise.

So, to summarize, any PA is better than none, the earlier you start in life, the better, PA is forever, combined training (aerobic and resistance) either on different days or in the same session (hybrid) is better than just individual form of PA, the greener the place, the better will be PA’s effect on your emotional and mental well-being and depending on what you want from your PA, the time of day may help achieve specific goals.

Footnotes

1. Gonzalez-Jaramillo N et al. Systematic Review of Physical Activity Trajectories and Mortality in Patients With Coronary Artery Disease. J Am Coll Cardiol. 2022 May 3;79(17):1690-1700.

2. Batrakoulis A et al. Comparative Efficacy of 5 Exercise Types on Cardiometabolic Health in Overweight and Obese Adults: A Systematic Review and Network Meta-Analysis of 81 Randomized Controlled Trials. Circ Cardiovasc Qual Outcomes. 2022 Jun;15(6):e008243.

3. Legrand FD et al. Effects of Outdoor Walking on Positive and Negative Affect: Nature Contact Makes a Big Difference. Front Behav Neurosci. 2022 Jun 3;16:901491.

4. Arciero PJ et al. Morning Exercise Reduces Abdominal Fat and Blood Pressure in Women; Evening Exercise Increases Muscular Performance in Women and Lowers Blood Pressure in Men. Front Physiol. 2022 May 31;13:893783. doi: 10.3389/fphys.2022.893783.