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Managing blood glucose and exercise in
young people with Type 1 Diabetes
Dr Alistair Lumb Dr Taffy Makaya
Anne Marie Frohock RD
May 2018
Plan
• Why might exercise be a challenge in T1
• What strategies do we have for dealing with this? • Before • During • After
• Technology and the future
• What can be done with T1?
Sports Workshop 2018
Sports Workshop 2018
How is this controlled?
• Variation in a number of hormones of which insulin is only one
• Other important hormones include adrenaline and noradrenaline (catecholamines) and glucagon
Sprinting, swimming sprints Weightlifting, Climbing Gymnastics, Fencing Athletics Field events
Football, Rugby, Hockey, Lacrosse Tennis, Squash, Rounders Running (middle distance) Playground games Skiing, Ice skating
Jogging/cross country Brisk walking, long walks Cycling, Marathon running Triathlon Skateboarding
Main fuel is carbohydrate from muscle glycogen
Fuel can be fat from stores and carbohydrate from blood glucose and
muscle glycogen
Muscle glycogen is a limited pool. Which is why
sprint-speed is not sustainable
Burning fat needs oxygen and takes
longer. Endurance exercise allows this
Blood Glucose DURING Exercise -Cardio and weights in the gym
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Yardley et al (2012) Diabetes Care 35: 669-675
Blood Glucose AFTER after exercise - Late hypoglycaemia
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Yardley et al (2012) Diabetes Care 35: 669-675
Blood Glucose AFTER after exercise - The Double dip
McMahon et al (2007) JCEM 92(3):963-968
BGs may drop 1-4 hrs afterwards
BGs may drop again 7-11hrs afterwards
BGs may be high immediately after
BGs may drop 1-4 hrs after
BGs may drop again 7-11hrs after
Exercise hormones remain elevated – Insulin Resistance
Anaerobic, sprinting or intermittent exercise
Pump off
As muscle stores of glycogen replenish
Blood Glucose AFTER after exercise - The ‘Whip, Double Dip‘
Sensitivity to insulin
remains increased
The hormonal response to a
falling glucose is not as strong
• Check • Check • Check!!
There is no other way
Before, During, After
Master your own diabetes
Sports Workshop 2018
Be prepared! • Practice your diabetes and exercise management plan
• Monitor glucose closely when you train and when you compete • Think about the intensity • Practice your refuelling plan • Learn your own patterns
• Make sure you are safe –
• if you have been hypo earlier in the day know the increased risk of hypo during training and consider going ahead.
• Be aware that things can change on “game day” (and practice dealing with this if you can)
• Expect the unexpected…
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• We don’t want to change the exercise, so we need to see
what we can do with the insulin and carbohydrate
We are balancing 3 things
Sports Workshop 2018
BG level 5-8 when starting exercise and throughout exercise
Aims of strategies
• Prevent hypoglycaemia after exercise • Prevent high BGs during exercise and afterwards
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5- 8mmol/l
Riddle and Pankowska Talk ISPAD 2012
Muscles work better, reactions are faster, you can train for longer and recover
quicker when BG levels are 5-8mmol/l
• Before, During, After
A number of factors which will affect the right management strategy:
• What is your BG now? Do you know what direction it is going in?
• When did you last eat? What did you last eat?
• What insulin do you have on board?
• What sort of exercise are you going to do? How long for?
Things to consider
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Before During After
BG below 4 Treat the hypo Only exercise when BG has recovered to above 5 mmol/l.
If you have been hypo earlier during the day be aware you are more likely to hypo during exercise
BG 4-7 Consider 10-15g extra carbs without insulin
BG 8-14 No extra carbs Drink plenty of water. Start low intensity exercise
BG over 8 Do not correct immediately after exercise After 2hrs, consider giving a small correction (half usual)
BG over 14 – CHECK KETONES Ketones over 1 mmol/l, do not exercise
Give a correction dose. Wait until ketones under 0.5 to exercise
Ketones less than 1 mmol/l, start low intensity exercise but drink plenty of water. For high intensity consider a correction dose (less than usual)
BG readings
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• Do not exercise at peak insulin action – (with significant Insulin on Board)
For aerobic exercise: • Reduce IoB by reducing bolus insulin if taken in the 2hrs
before exercise • Reduce basal insulin 90mins before if able
For anaerobic exercise: • No bolus reduction may be needed
Insulin
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Normal dose
Insu
lin le
vel
Time (h)
Effect of lowering insulin by 50%
1 2 3
Reduced dose
Fast acting insulin
Basal insulin
Basal insulin – aerobic activity
MDI • Generally not advised to reduce basal insulin prior to activity • Would only recommend this for extended periods of aerobic activity
(e.g. activity weekends, skiing holidays)
Insulin pump • Ideally reduce basal rate 60-90 minutes before exercise • Best reduction will be individual, starting point reduction by 50-
80% • Can remove pump, but think about reconnecting approximately
every hour to replace missed basal
Sports Workshop 2018
Before During After
Bo
lus
Reduce insulin for food eaten within 90 mins of exercise – by 25-50%
Do not give bolus insulin
Reduce insulin for food eaten at the meal following exercise by 25-50%
Bas
al
Reduce basal rate 90 mins before by 50-75%
Reduce basal insulin rate by 50-80% (keep pump on if possible – if not replace half missed basal as a bolus before you take it off)
If intense afternoon or evening exercise Reduce long acting insulin by 10% Or Reduce basal rate at bedtime for 4hrs by 20%
Insulin – PLAN if you can
Sports Workshop 2018
Before During After
Depends on BG & exercise & IoB BG 4-5 = 10-15g snack (fast/medium) BG 5-8 & exercise >30 mins = 10-15g snack (medium) BG >8 = no extra carbs – drink plenty of water
For exercise over 1hr extra carbs are likely to be needed. May be sooner if strenuous or no insulin adjustments made 0.5 g/kg/hr for every hour over the first hour FAST acting
Hydrate through the day with water
Hydrate with fluids Water should be adequate for exercise under 1hr Longer duration (over 1hr) switch to sports drinks
Carbohydrate
Exercise Nutrition - Snacks
• Medium acting
– Cereal bar (20-30g carb)
– 30g raisins (20g carbs)
– Banana (25g carbs)
• Fast acting
– 30g Jelly beans (25g carbs)
– Sports energy gels
– Glucose tablets
• Sports Drinks
– Fast carbohydrate for longer events (30g carbs in 500ml)
– Isotonic – improves hydration – GI side-effects – Easy to over-do it – BGs too high
Hydration
Water
Fine for shorter events
No side-effects
Using exercise to help you
• If glucose is high before activity – you can use a low intensity warm-up to help bring this down
• If on the low side – can you use a 10s sprint to help you?
• If going to the gym – can you adjust the order in which you do things?
Sports Workshop 2018
Sports Workshop 2018
The 10 second sprint
7
6
5
4
3 Blo
od
Glu
cose
Le
vel (
mM
)
Time (min)
A
a a
a
a a a a a a
a
Insulin release is able to control glucose rise in people without T1
Without insulin administration, glucose rise is unchecked in people with T1
7
6
5
4
3 Blo
od
Glu
cose
Le
vel (
mM
)
Time
B
b b b b
Fahey et al., J Clin Endocrinol Metab, 2012
Before During After
Bo
lus
Reduce insulin for food eaten within 90 mins of exercise – by 25-50%
Do not give bolus insulin
Reduce insulin for food eaten at the meal following exercise by 25-50%
Bas
al
Reduce basal rate 90 mins before by 50-75%
Reduce basal insulin rate by 50-80% (keep pump on if possible – if not replace half missed basal as a bolus before you take it off)
If intense afternoon or evening exercise Reduce long acting insulin by 10% Or Reduce basal rate at bedtime for 4hrs by 20%
Insulin – Insulin sensitivity increases after exercise so you need less of it!
Sports Workshop 2018
Before During After
Depends on BG & exercise & IoB BG 4-5 = 10-15g snack BG 5-8 & exercise >30 mins = 10-15g snack BG >8 = no extra carbs – drink plenty of water
For exercise over 1hr extra carbs are likely to be needed. May be sooner if strenuous or no insulin adjustments made 0.5 g/kg/hr for every hour over the first hour FAST acting
‘The Golden Hour’ 10-15g carbohydrate without insulin And PROTEIN Meal/snack
Hydrate through the day with water
Hydrate with fluids Water should be adequate for exercise under 1hr Longer duration (over 1hr) switch to sports drinks
Carbohydrate
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• Replenish stores of glycogen in the body
• Eat carbohydrate within 1-2 hours of exercise
– Aim is 1g/kg bodyweight to replenish stores
• Include protein with this to reduce risk of ‘double dip’ hypos
After exercise - ‘The Golden Hour’
Sports Workshop 2018
• If you are eating a full meal:
– Include carbohydrate (1g/kg)
and protein (20g)
– Reduce the dose of insulin by 50%
• If not eating a meal
– Eat a 10-20g carbohydrate snack without insulin - include some protein with this snack
Eating during the Golden Hour
Sports Workshop 2018
• Milk shakes (300-400ml)
• Cereal (or cereal bar) and 200ml milk
• Nutty cereal bar
• Fruit and Nut mix
• Yoghurt and fruit
• Cheese and crackers
• Peanut butter sandwich
• Beans on toast
• Meat/fish sandwich
Golden Hour Snack ideas
• Check • Check • Check!!
There is no other way
Before, During, After
How do I know it works?
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Overall nutrition
• Youngsters have high energy requirements for growth • It is recommended about half of this energy comes from
carbohydrate
• Exercise increases energy requirements further
• For optimal growth, exercise performance and recovery – we must ensure that nutritional intake is adequate for exercise to be undertaken
Hydration is essential too
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Recommended energy requirements
Diabetes, Obesity and Metabolism (2011) 13:130-136
Age EAR - boys Guideline carb intake (g/d) EAR - Girls Guideline carb intake (g/d)
kcal/d kcal/d
1 765 717
2 to 3 1088 122 - 145 1004 113 - 134
4 to 6 1482 166 - 198 1378 155 - 184
7 to 10 1817 204 - 242 1703 191 - 227
11 to 14 2500 281 - 333 2000 225 - 267
15 to 18 2500 281 - 333 2000 225 - 267
* Calculations based on SCAN DRV for energy (2011) population based average activity levels
with 45-50% total energy from carbohydrates
Energy requirements for 11-18yr olds are capped at 2500kcal/2000kcal per day to address issue
of overweight/obesity
Sports Workshop 2018
• Chance to review plans and make adjustments
• Chance to respond to changing situations in real time
• Less accurate during exercise due to rapidly changing BG levels • Time lag between Blood Glucose and Sensor glucose
CGM and Exercise
How could we use real-time info?
Adapted from: Riddell & Milliken (2011) Diabetes Technology and Therapeutics 13(8):813-825
Sports Workshop 2018
Sports Workshop 2018 https://www.justgiving.com/crowdfunding/diathlete100
Marathon Man!
Gavin Griffiths lives with type 1
diabetes and will be running 25
marathons around the UK & Ireland in
a month between 13 April & 13 May
2018 in the #DiAthlete100 challenge -
which if successful will total Gavin's
100th endurance triumph for type 1
diabetes in the last 10 years! A
milestone of diabetes empowerment.
https://www.teamnovonordisk.com/team-novo-nordisk-changing-diabetes/