Exercised by Daniel Lieberman

Link to notes. 

Quick reference: 

Classifying activity levels depends on the method being used.

One standard convention is based on percentage of maximum heart rate:

• less than 40 percent is sedentary;
• 40 to 54 percent is light activity;
• 55 to 69 percent is moderate activity;
• 70 to 89 percent is vigorous;
• and more than 90 percent is high.

Maximum heart rate is sometimes measured but usually estimated from age.

A common formula for maximum heart rate is to subtract your age from the number 220,

but for healthy adults a better equation is 208 – 0.7 • age.

At age 53, my estimated max HR = 171.