When you take a medication, like Tylenol for a headache, there are dosing recommendations you follow. That makes sense, because you want to take enough to make your headache go away. But taking too much can be dangerous. Lethal even. Here are the dosage recommendations for Extra Strength Tylenol:

2 Caplets Every 6 hours while symptoms last.
Not to exceed 6 caplets in 24 hours, unless directed by a doctor.

How much is needed to have an effect? How much to cause harm? A big part of the research that goes into a new pharmaceutical before it hits the market determines these recommendations.

We’ve been given similar instructions for exercise for years now. The recommended dose of exercise is at least 150 minutes of moderate exercise or 75 minutes of vigorous activity per week.

But there was not a double-blind, placebo-controlled study to determine the optimal amount. There was never a maximum amount of exercise you shouldn’t exceed. And if you only walked for ten minutes five times a week, you were left to wonder if it was even worth it.

If we look at exercise like medicine, we want to know what dose of it will be effective and if there is a dose that might harm us.

Two major pieces of research were published last month in the Journal of the American Medical Association shed light on the dose/response relationship of exercise to longevity.

The first study pooled data collected from six studies in the National Cancer Institute Cohort Consortium. It looked at self-reported exercise information on over 660,000 patients with an average age of 62. Then it looked at death rates over an average 14 year follow up. The data revealed the following:

  • People who exercised a little - less than the 75/150 minute recommendation - were still 20% less likely to die than those who didn’t exercise at all.
  • People who exercised in the range of one to two times the recommended numbers were 31% less likely to die than those who did not exercise at all.
  • People who got two to three times the minimum were 37% less likely to die.
  • The sweet spot was found by people who exercised three to five times the minimum. They gained a 39% benefit from the exercise.

After this peak range, people who exercised more never saw much additional benefit. But there was no maximum exercise threshold that, if crossed, led to harm.

The second study was conducted in Australia and followed over 204,000 adults aged 45-75 for an average of 6.5 years. It found similar benefits for physical activity, but took it a step further and looked at the inclusion of vigorous activity in the workout. They found the following:

  • Those who exercised at all but included no vigorous activity had a death rate of 3.84%.
  • Those who included some vigorous activity had a death rate of 2.35%.
  • Those whose exercise included at least 30% vigorous activity enjoyed the lowest death rate at 2.08%

To be clear, there are accepted definitions of “moderate” and “vigorous” physical activity. Moderate suggests a brisk walk or mowing the lawn (no riding mowers allowed). Vigorous exercise includes jogging at around 6 miles per hour or playing a casual game of soccer. For more examples, the Harvard School of Public Health has put together a handy chart for us to see where our favorite exercise falls. I was sad to see sitting at desk behind a computer rated so poorly.

We have some good data now on where the exercise sweet spot might lie. Official recommendations are yet to be made by medical organizations based on this relatively new information. Even so, it seems smart to incorporate their findings into your routine.

So what’s the take away? Get a little more than an hour of exercise per day, with about 30% of it vigorous if you want your routine to match the sweet spot these studies revealed. But, if you can’t do that, something is definitely better than nothing. So go take a walk, and make it a brisk one.