Table 1.

Categories of Physical Activity For Youth Aged 8–18 Years

Intensity category	Description	Example activities	Measures (mean values for age 8–18 years)
Sedentary	Waking behavior typically performed in a sitting, reclining or lying posture.	Sitting or reclining while watching television, playing video games, driving, reading and fishing.	< 1.5 METs
			<40% HRmax
			<20% HRR
			<20% V̇O2max
			RPE: < 8
Light	Light aerobic activity that does not cause a noticeable increase in breathing and can be sustained for atleast 60 minutes.	Domestic or occupational tasks such as washing dishes, ironing, working at a desk or performing office duties	1.5 to 4 METs
			40 to 63% HRmax
			20 to 39% HRR
			20 to 45% V̇O2max
			RPE: 8 to 11
Moderate	Aerobic activity that can be sustained while maintaining a conversation uninterrupted.	Gentle swimming, social tennis and golf.	4–6 METs
			64 to 76% HRmax
			40 to 59% HRR
			46 to 63% V̇O2max
			RPE: 12 to 13
Vigorous	Aerobic activity during which a conversation cannot be maintained. An intensity that may last up to 30 minutes.	Jogging, aerobics, fast bicycling, resistance training, competitive sports	6–9 METs
			77 to 95% HRmax
			60 to 89% HRR
			64 to 90% V̇O2max
			RPE: 14 to 17
Near-maximal to maximal	Activity that typically cannot be sustained for longer than 10 minutes.	Sprinting, periods of competitive team sport activity.	≥ 9 METs
			≥ 96% HRmax
			≥ 90% HRR
			≥ 91% V̇O2max
			RPE: ≥ 18

Notes: Table adapted from Norton and colleagues,¹⁶ ACSM,¹⁶³ Butte and colleagues,¹⁷ and Eather and colleagues.¹⁸ The reported MET values in this table were derived from the Youth Compendium of Physical Activities for specific activities and adapted by Eather and colleagues.¹⁸ Children undergo systematic changes in body composition as a result of growth and maturation, which has implications for activity intensity classifications. As such, MET cut-points should be adjusted for differences in resting energy expenditure. Youth METs have been adjusted to account for the unique physiological characteristics of children and adolescents; % HRmax, percentage of heart rate maximum (heart rate maximum = 220 – age); %HRR, percentage of heart rate reserve (heart rate reserve = HR_max − resting HR); %V̇O_2max, percentage of maximum oxygen uptake. Borg’s Rating of Perceived Exertion (RPE) scale, ranging from 6–20.^{45, 164–166}