Exercise is known to be good for us, but how much exercise and is...

Exercise is known to be good for us, but how much exercise and is there something like too much exercise?

Exercise is often seen to have a J-shaped curve with mortality risk - not enough is bad but too much is also harmful (PMID: 26187713)

How much is optimal then?⬇️⬇️

The guidelines recommend adults get 150-300 min/week of moderate exercise or 75-150 min/week of vigorous exercise

Meeting that vs not is linked to a 36% lower odds of being overweight and 48% lower odds of being obese (PMID: 37773071)

However, exercising more than that is linked to a reduced risk of mortality

A 2022 study saw the lowest risk of mortality at 150-300 min/week of leisurely vigorous physical activity, 300-600 min/week of leisurely moderate physical activity, or a combination of both (PMID: 35876019)

A 2023 review on adults 65 and older found a 40-60% reduction in all-cause mortality risk at 60 MET-hours per week (PMID: 37925162)

1 MET = 3.5 ml/kg/min of VO2 max
10 METs= running at 6 mph or 9.6 km/h

To reach 60 MET-hours of physical activity, you can either do 6 hours of 10 METs (35 ml/kg/min), 12 hours at 5 METs (17.5 ml/kg/min)

However, it's important to differentiate between vigorous and moderate physical activity

A 2023 systematic review found that the more moderate physical activity the lower your all-cause mortality risk (PMID: 37091937)

It even outperformed vigorous activity at high levels (-17% at 650 min/week vs -35% at 900 min/week).

For cardiovascular disease mortality, the more moderate physical activity, the lower the risk (-40% at 900 min/week)

For vigorous physical activity, the benefits were maximized at 150-200 min/week (-15%). After that there was a reduction in benefits.

A similar phenomenon is found with resistance training with too much being linked to higher risk

At 30-60 min/week, strength training is associated with a 17% lower risk of all-cause mortality, 18% for CVD events, and 9% for all cancer (PMID: 35228201)

However, you see higher risk above 130-140 min/wk.

This data is very limited because we don't know what does it entail in terms of rest between sets, amount of reps, etc. because the studies weren't standardized for this.

But the general idea that there is a U-shape for benefits is probably true

It seems that you don't get progressively more benefits the more vigorous exercise you do – you hit a plateau after 200 min/week but doing less is worse.

However, you do keep getting benefits the more moderate exercise you do (900 min/week is better than 200 min/week).

Instead of trying to do more high-intensity exercise, it’s better to keep it between 100-200 min/week and focus on racking up as much moderate physical activity as possible.

Moderate exercise is categorized as 40-60% of aerobic capacity, whereas vigorous exercise is 60-85%