Sedentary Behaviour And Health

Question 1

What is sedentary behavior?

Answer 1

Definition: any waking activity that requires an energy expenditure of smaller or equal to 1.5 METs，at a sitting or reclining posture.

Question 2

Describe the trends shown in sedentary behavior through time?

Answer 2

Increasing over time…

1. We used to use walking and cycling as modes of transport. Now cars replace the foot.
2. Key words in searches of journal articles including ‘sedentary’ increases dramatically.
3. More jobs involving being sedentary and light intensity activities. Conversely, moderate intensity decreases.

Question 3

As an exercise and sports professional, which are easier? Moderate, light or vigorous intensities for our general populations? Provide reasons.

Answer 3

Our focus should be on light and moderate activities.
Light and moderate: can do indoors (minimal requirement of facilities), cost none or minimal, time spent least, least requirement or no requirement of skills and experience. Also benefit some people who are physically limited.

Question 4

What is the difference between inactive and sedentary?

Answer 4

V

Question 5

Describe the ‘sedentary active’ phenotype?

Answer 5

An activity pattern common to people who has a job involving long sitting hours, but goes for at least one bout of moderate to vigorous exercise throughout one day. For example, sitting at an office for 11 hours and goes for a 40 minute run or jog after work.

Question 6

Overview of the evidence on sedentary behaviour and health?

1) mortality?

Answer 6

1. Greater than 4 hours of screen time —>significant increase of all cause mortality.
2. Every one extra hour of sitting leads to 2 % mortality risk.
3. Risk of death negated if active levels reach certain levels and goes up.
4. Only sig risk of death if combined with low/no level of activity.
5. If you are inactive and are sedentary for above 11 hours, then sig. risk. But if activity level reaches the guidelines then it becomes insignificant.

Question 7

Cardiovascular?

Answer 7

Same

Question 8

Diabetes?

Answer 8

Uncertain, because there are evidence suggestive of impaired glycemic control, but not sufficient.

Question 9

Mechanisms explaining why sedentary behaviour alone isn’t enough as a risk factor?

Answer 9

Many evidences:

Refer to lecture slides.