Recently a study was published in JAMA that followed a total of 661,137 people (median age: 62 years; range: 21-98 years) comparing weekly aerobic exercise and mortality.
The results are pretty shocking- in a good way. Doing just a bit of vigorous exercise per week has a dramatic impact.
Here is what these data shows:
You get the most bang for your buck at just 75 minutes per week
The study showed is that completing just 75 minutes of aerobic exercise a week reduces mortality by 20%. Doubling that reduces mortality by an additional 11% and tripling it reduces mortality by an incremental 7%. After that the benefit flat lines.
This means that you get most of the benefit of being active if you do something for just 1 hour and 15 mins per week- and the range of activites that qualify include anything from running to heavy gardening.
There is strong evidence that exercise causes mortality to drop
Many times studies fall into the correlation but not causation camp. The way to evaluate causation is to look at something called the Hills Criteria of Causation. The Hills criteria lays out ways to determine whether or not a factor is causative. One of the strongest ways to evaluate causation is a dose response. Meaning, if more is administered a bigger impact is seen. These data show a strong, clear dose response between exercise and a drop in mortality.
Ways to hit your quota
Mix up your cardio routine by adding high intensity interval training (HIIT)– an exercise method that alternates high intensity intervals with low intensity recovery periods. Download an interval timer and use the structure below:
Warm up by jogging for 5 minutes. Sprint at maximum capacity for 30 seconds.
Walk or jog for 60 seconds.
Repeat for a total of 30 minutes.
This timing can be used with any exercise: on the elliptical, the exercise bike, or the row machine at the gym. It can also be done for body weight exercises such as squats, lunges, or pushups. As you get accustomed to HIIT training, you can shorten the recovery periods. Want to make it easier? Tell a friend why you are doing this. It’s proven to make the habit stick.
Do this twice a week with 15 minutes of brisk walking and you are there.
A few data notes
At the extreme part of the scale it looks like mortality rate increases. The key is to look at the confidence interval here. This study shows no increased risk of doing 12.5 hours of exercise.
We used the top end of the ranges to plot the data. Meaning if the data said 2.5-3.75 hours of exercise we plotted it at 3.75. We did this in an effort to avoid misleading people that less exercise is necessary to reduce risk. Refer to the results section in the article for the full data set.
Exercise for 75 minutes to maximize mortality reduction per minute.