L293 Exercise Benefits vs Risks

Question 1

Risks and harms vs benefits with ex: when are they highest?

Answer 1

Both with athletes

Question 2

Greatest increase in benefit with ex seen when?

Answer 2

With mild-mod ex

Question 3

Effect of ex on insulin action

Answer 3

↑ insulin sensitivity with ex

Question 4

Possible mechanisms of enhanced insulin action with exercise (7)

Answer 4

1. Insulin signalling (Akt?, AS160?)
   
   • Distal insulin signalling pathways altered by ex
2. ↑ GLUT4 expression
   
   • muscle and adipose tissue
3. ↑ Hexokinase, glycogen synthase activities
4. ↑ Muscle oxidative capacity
5. ↑ Muscle BF
6. ↑ Capillary density/recruitment (→ ↑CSA for insulin to act)
7. ↑ NO/NOS

Question 5

Insulin resistance and sensitivity: what happens

Answer 5

• Sensitivity: more glucose taken up as glycogen in muscle and liver
• Resistance: more glucose taken up as fats in liver → hypertriglyceridaemia

Question 6

Consequence of ex effect on insulin action

Answer 6

↑ muscle insulin sensitivity → ↓ hypertriglyceridaemia and allows glucose to be used more efficiently by muscle

Question 7

Effect of ex on HDL

Answer 7

ex doesn’t only ↓ TGs (bad), but ↑HDL (good)

Question 8

Aside from increased insulin sensitivity, how might ex reduce TGs?

Answer 8

↑lipoprotein lipase in trained → ↑TG clearance

Question 9

Effect of ex on central obesity (and how)

Answer 9

↑ ex → ↑ E ex → ↓ central obesity

Question 10

Effect of ex on BP

Answer 10

↑ ex → ↓SBP and DBP: i.e. ex has a significant BP lowering effect

Question 11

Comment on the anti-inflammatory effect of ex, and the difference between mod and high levels of ex

Answer 11

• ↑IL-6 with ex (good thing - but prolonged elevation is a bad thing)
• Mod levels of ex has anti-inflammatory effect
• High levels of ex might have immune suppressive effects
- E.g. ↑ frequency of URTI in excessively trained athletes

Question 12

Risks associated with exercise (list some examples, 7 in total)

Answer 12

1. SCD
2. Exercise-induced bronchospasm (asthma)
3. Musculoskeletal injury
4. Delayed onset muscle soreness
5. Exertional rhabdomyolysis
6. Exertional hyperthermia / hypothermia
7. Proteinuria (changes in glom membrane function)

Question 13

Which period after ex bears most risk?

Answer 13

Immediate post ex

Question 14

Which period during ex bears most risk?

Answer 14

First hour or so

Question 15

Relationship between ex and injury

Answer 15

↑ ex frequency and duration → ↑ injury risk

Question 16

Ex: risks vs benefits

Answer 16

• Yes, more ex means more risk suddenly

- But, LT benefits outweigh risk of injury/adverse events