Having recently been asked about calorie usage, and following an unsuccessful online search for a table of PAR values, I have reproduced, below, one I had in my physiology notes from a few years ago. Using PAR allows a much more accurate calculation of TEE or PAL than the typically limited ‘activity levels’ (e.g. sedentary, lightly active, etc.) commonly seen (as well as providing some meaning/context for the PAL values).
Basal metabolic rate (BMR): The necessary energy to maintain body functions while awake, but under conditions of rest (with sufficient fasting to avoid the effects of food intake on metabolism) for an individual (typically factoring in mass, height, age, and gender).
Clinically, metabolic rate is typically determined through oxygen (O2) consumption. With each litre of oxygen consumed corresponding to approximately 4.8kcal of chemical energy liberated.
Formulas for BMR provide an estimate, the one below is the Mifflin equation:
Total energy expenditure (TEE): The average energy an individual spends in a 24-hour period (i.e. the average energy used in a typical day – may be averaged from a group instead of individually).
Physical activity level (PAL): TEE divided by BMR (for 24 hours) – expressed as a multiple of BMR. Alternatively, one can calculate a weighted average of PAR values over a ‘typical’ 24 hour period to get a reasonable estimate of PAL.
Physical activity ratio (PAR): The energy requirements for a given activity expressed as a multiple of BMR (i.e. energy spent/BMR, over the same unit of time)
PAR Values for Common Activities
|B.M.R. Multiplier (PAR)|
|Awake, lying still||1.2|
|Sitting – at rest||1.4|
|Sitting – and reading||1.7|
|Sitting – and writing or taking notes or homework||2.1|
|Sitting and eating||2.2|
|Sitting and typing (rapidly)||2.3|
|Dressing and undressing||1.8|
|Driving (a car)||2.0|
|Dishwashing, ironing, etc.||2.2|
|Cycling (for fun)||3.1|
|Vacuuming, sweeping, or cleaning house||4.0|
|Dancing (moderate speed)||5.0|
|Horseback riding (moderate speed)||7.2|
|Playing ping-pong (competitively)||17.5|
|Skating (speed skating)||18.0|
|Horseback riding (hard)||22.0|
Stairs – not based on B.M.R.:
|Walking up stairs:||0.014Cal/kg/3 steps|
|Walking down stairs:||0.004Cal/kg/3 steps|
Fat has an energy density of 9.4kcal/g – but, due to water content, adipose tissue is normally taken at about 8kcal/g – this works out to just over 3600kcal/lb or around 8000kcal/kg.
A final point of mention – the ‘calorie’ (Cal – note the capital ‘C’) used in nutrition is actually a kilocalorie (kcal – note the lowercase ‘c’): 1Cal = 1kcal= 1000cal. By definition a calorie (cal) is the amount of heat (energy) needed to raise the temperature of 1g of water by 1°C.