Lab Class 4: energy balance and expendature

Question 1

According to ACSM, how much of a reduction in weight is required to see a decrease in health risks?

Answer 1

3-5%

Question 2

How many minutes per week should a person exercise for to cause clinically important weight loss

Answer 2

250 minutes

a dose response effect of exercise duration is present

Question 3

How long do ACSM guidelines recommend exercising for, for the purposes of weight maintainance following weight loss

Answer 3

250 mins

Question 4

how does resistance training reduce health risk, even though it does not contribute to weight loss

Answer 4

loss of fat mass
increase in muscle mass and therefore and increase in basal metabolic rate so increase in energy expenditure
improved insulin sensitivity

Question 5

what three components make up total body energy expenditure

Answer 5

RMR
thermic effect of feeding
voluntary activity (PA and recovery)

Question 6

what is the definition of RMR

Answer 6

energy expended at rest, measured 3-4hrs post meal without any prior PA

Question 7

what is RMR slightly higher than BMR

Answer 7

BMR is measured 12hrs post meal to avoid any energy being expended during digestion and absorption of food

Question 8

why is important to know about RMR when calculating energy balance and expendature

Answer 8

to determine net energy expenditure from PA accuratly

gross energy expenditure - RMR

Question 9

outline how RMR can be calculated

Answer 9

participant sits at rest for 5 minutes

then breaths into Douglas bag for 5 minutes

air analysed for % O2 and CO2 by gas annalyser

machine gives an R value, look this up in the table to give the number of kcal burnt/lO2 consumed

multiply kcal by resting VO2 l/min to give calories burnt per min

multiply up to determine how many burnt in 24hrs

Question 10

what is the definition of a MET and how many calories would a 70kg person burn if exercising at 3 METS for 1 hour

Answer 10

a multiple of the resting metabolic rate

= 1kcal / kg / hour

so exercising at 3METS would burn 210 kcal in a 70kg person (gross expendature)

Question 11

what is the equivalent of 1 met, if expressed in terms of O2 consumption

Answer 11

3.5ml / kg / min

Question 12

Approximately how many calories are burnt for every litre of oxygen used

Answer 12

5

Question 13

One calorie is equivalent to how many KJ

Answer 13

4.184

Question 14

How long do ACSM recommend exercising for to prevent weight gain

Answer 14

At least 150 mins per week