Table 1.

Intensity of physical activity

Intensity	Aerobic activity			Muscle-strengthening activity
	%HRmax	Talk test (comfortable conversation)	Compendium of physical activities
Sedentary	<50	Possible	≤1.5 METs
			- Sitting, playing traditional video game, computer game (1 MET)
Light	50–63	Possible	<3 METs	40%–50% of 1 RM
			- Watering plants (2.5 METs)
			- Walking to and from an outhouse (2.5 METs)
Moderate	64–76	Possible	3–5.9 METs	60%–70% of 1 RM
			- Walking a dog (3 METs)
			- Walking at 3.5 mph briskly on a firm surface (4.3 METs)
Vigorous	77–93	Not likely possible	6–8.8 METs	≥80% of 1 RM
			- Race walking (6.5 METs)
			- Walking at 4.0 mph very briskly on a level, firm surface (6.8 METs)
			- Jogging (general) (7.0 METs)
Very hard to maximum	>93	Not possible	≥8.8 METs
			- Running a marathon (13.3 METs)

The compendium of physical activities is a list of physical activities quantifying the energy cost as MET values (1 MET=3.5 mL/kg/min of oxygen uptake).

%HR_max, percent of maximum heart rate (HR_max=220−age); MET, metabolic equivalent; 1 RM, one-time repetition maximum (the heaviest weight a person can lift once).