Exercise and Diabetes Flashcards
What are the standard exercise recommendations for adults?
-150 minutes/week of mod-vig activity with no more than 2 days off in a row and strength training 2-3x/week
What are the standard exercise recommendation for youth?
-60 mins/day of mod-vigorous activity, with 3+days/week strength building activities
What are 5 benefits of exercise in diabetes?
- Weight management, increase LBM
- Reduced CVD risk factors (lower BP, better lipid profile)
- Improved insulin sensitivity
- Psychological benefits
What are the 4 challenged of exercise in diabetes?
- Injury
- Impact on A1C varies
- Hypoglycemia
- Hyperglycaemia
What is the number 1 reported barrier for exercise for those with diabetes?
Hypoglycemia
Discuss exercise impact on overall A1C management
-Exercise may have a beneficial effect, however the beneficial effect may be mitigated by attempts to avoid hypoG
(T/F) Exercise in diabetes is the most beneficial, and poses the least risks to T1DM
F
T2DM
When can hypoG occur during exercise?
- Immediate-during or right after exercise
- Delayed “lag effect”
When can delayed hypoG occur after exercise?
-6-15 hours after exercise, with an average of 7-11 hours after activity, and usually overight
BG trends after aerobic exercise? What are the main variables?
- Trends down
- Intensity, duration, I:G ratio, fitness, initial glucose concentration
BG trends after mixed exercise? What are the main variables?
- Trends upwards (with anaerobic) and downwards (with aerobic)
- Same as aerobic, plus lactate concentration and counterregulatory hormones
BG trend after anaerobic exercise? What are the main variables?
- Trends upwards
- Same as mixed, but intensity and number of intervals and I:G ratio is not considered
When a healthy person exercises, how does insulin concentrations change?
Naturally, they will physiologically decrease allowing us to maintain a stable blood sugar
-In diabetes, we need to mimic this physiological mechanism
Discuss the dysregulation which occurs leading to hypoglycemia in exercise in diabetes?
1) Absence of physiological decrease in insulin secretion
2) Increased absorption of insulin from subcutaneous area (due to increased blood flow)
3) Increased transport of glucose transport into the muscle, and diminished hepatic glucose production’
4) Hypoglycemia
5) Blunting of counter-regulatory hormones in patients with T1D
Discuss the trends seen in Glucose Infusion Rates (GIR) to maintain euglycemia
- There are biphasic glucose requirements
- We will require more glucose to maintain euglycemia right after exercise to avoid early hypoG risk
- We will require more glucose ~10 hours later in order to avoid late hypoG risk
- GIR is inversely proportional to BG levels
During sleep and after exercise, how are those with T1DM affected? (4)
- Have increased glucose requirements (incr. insulin sensitivity, glycogen restoration)
- Impaired counter-regulation
- Relative excessive circulating insulin
- Absence of CHO intake
- –> Strategy could be to have small 15-20 g CHO snack prior to bedtime
Discuss 5 factors which can affect the BG response to exercise
- Duration/intensity
- Type of activity
- Metabolic control
- BG at time of exercise
- Timing/type of insulin and timing/type of food
If we are going for a run, and inject insulin into our legs how may this affect glucose levels?
-May encourage a quicker onset of hypoG due to increased blood flow to the legs
A patient presents with recurring hypoglycemias after exercise (which she corrects with extra snacks) and is finding this counterintuitive to her weight-loss goals, what could we recommend to control BG and encourage weight-loss?
- Suggest to decrease bolus insulin at meal prior to exercise (start with higher BG)
- Go over how many CHOs are really required after exercise (15-20 g CHO)
- Recommend small snack after exercise only if not eating in the next hour
- Suggest anaerobic/sprint after exercise to increase BG and avoid hypoG
A patient presents with recurrent post-exercise hyperglycemia, followed by nocturnal hypoglycemia (injecting insulin after exercise to combat high BG). The patient would like to gain muscle and wants to avoid hypoGs as it affects his performance the next day. Why does this happen? What are your recommendations? The patient is on an insulin pump
- He is finishing his exercise with anaerobic exercise, therefore BG are high, and he is then overcompensating for high BG by injecting insulin after exercise and then later at dinner, causing nocturnal hypoG
- We can recommend patient to do an aerobic cool own to bring BG levels down. The aerobic exercise will increase the demand for glucose.
- We should also investigate if the patient is suspending their insulin pump, and ensure they are doing so appropriately
- Advise patients that bolus insulin is usually not req. after exercise, and our BG will naturally come down
Both _____ and ____will increase glucose uptake into skeletal muscle
- Insulin
- Muscle contration
Discuss the increased insulin sensitivity and muscle glucose uptake during exercise
- Usually we will require insulin to signal GLUT4 transporters to the membrane for glucose uptake
- However, during muscle contraction, GLUT4 will be brought to the membrane with less insulin, and there will be an increased flow of blood bringing glucose into the cells
- Therefore, we will require less insulin during exercise
- In diabetes, we need to mimic this mechanism
What is the decline in plasma glucose in DM during exercise associated with?
-Impaired glucose production (as elevated insulin levels will suppress glycogenolysis and gluconeogenesis) alongside increased glucose uptake (normal mechanism of insulin, enhanced by increased insulin sensitivity with muscle contraction)
Discuss post-exercise glucose uptake
remains elevated for hours to replenish muscle glycogen stores
After exercise, why do our glucose requirements remain elevated?
- The receptors are still sensitized, and we need to replenish our muscle glycogen stores
- Therefore, there is a risk of hypoglycemia later on
- Recommend snack after exercise
What does aerobic exercise without adjusting insulin cause?
Variable drop in glucose, which may cause hypoglycemia
(T/F) In non-diabetic patients, blood sugar will drop in aerobic exercise as there is increased utilization of glucose in muscles
F
Blood glucose will remain relatively constant, as in healthy individuals our insulin secretion will decrease, therefore the increase uptake of glucose in the muscles is counteracted by hepatic glucose output
In T1DM with no insulin adjustment in aerobic exercise, what is the average change in blood glucose over 75 minutes? What is a key concept?
- Approx. 3.6 mmol/L decrease, where 40% will become hypoglycemic
- There is a large variability, some will drop more and some will drop less
- requires trial and error
- Sometimes, will not have the same response twice to the same exercise, therefore hypoG is hard to predict
(T/F) In trained, T1DM patients with good physical fitness, they will see no glucose drop after aerobic exercise
F, the glucose drop is still present in patient with high fitness