SPORT & TYPE 1 DIABETES
There can be many questions and differing outcomes (which means more questions) when it comes to Sports & Exercise with type 1 diabetes.
With many factors to consider from timings of insulin doses, nutritional decisions, types of activities and, more so, the types of movements performed within those activities (where every performance might differ to the next), we believe the best approach is to breakdown each detail and customise them to your personal routines to find the best solutions. This page will share key guidelines both scientifically and from shared experiences.
Preparations with T1D:
Gavin Griffiths, founder of DiAthlete and ultra-endurance runner who has lived with type 1 diabetes for over 20 years shares his thoughts on preparations before any exercise:
“There are a lot of differing areas to consider when it comes to sports or exercise in general with type 1 diabetes. Pre-activity preparation does not only mean doing the standard warm ups before a game or workout as an athlete, but with diabetes in the equation it means planning for your routines in advance where possible.
Having an added focus of ‘diabetes discipline’ on your particular sports days can set you into the best positions for balancing glucose levels before, during and after activity – and more so, performing to your best as a result. Let’s make it clear to begin, living with type 1 diabetes does indeed require a lot of added responsibility, yes, but with this you CAN perform to any level and achieve any life goals you have.
- Consider the activity you are to do in advance: likely duration of it, the competitiveness & intensity, the types of movements whether aerobic or anaerobic. Are we talking a team sport at a weekend, such as a football or rugby fixture, or are we planning for an endurance challenge such as a marathon, or a fitness routine from the differing elements of weight lifting to cardio?
- Being strict on your timings in advance. This applies for both timings of meals and timings of insulin doses. With meals, to start for any athlete, you do not want to be going into a sports game without having had a chance to digest! More so, you do not want to be going into a sports event with an over active / imbalance of insulin in your system, which then negatively impacts your levels during (if not before) activity. Making a plan for the type and timing of meal and insulin regime with it in advance is a major help.
- Types of meals in advance. As a marathoner I am not just looking at my breakfast in ‘preparation.’ I am also considering the likely duration and level of intensity in my activity – I have taken some challenges where I’ve been out active for up to 12 hours! – and so I am looking at the meals on the day before, particularly for dinner meals the night before an activity. To make sure I’ve a good boost for a challenging endurance exercise like half or full marathons, trail, hiking, triathlons, ultras etc, a fuelling meal such as a pasta bowl could be recommended, to build the glycogen storage. For pre-meals in all sports, I do not recommend the higher fat content meals in advance as this for one may not respond best during movements, but furthermore where diabetes is concerned, this can cause an unpredictable outcome and blood glucose spikes closer to / during / or even just after activity (whether aerobic or anaerobic). I recommend for pre meals to have a more ‘faster acting’ but substantial carb meal, such as porridge or eggs and beans on toast, timed 3 hours beforehand.
- Starting in range. Easier said than done! But I don’t aim to start higher in levels, despite the potential of levels dropping in many forms of activity. I want to do my best to start in a good, healthy blood glucose range – perhaps aiming to steer above the 5 mmol/l mark as a safety net, and targetting around 6mmol/l to 8.5 mmol/l as a strong start point. Simply put: being in range is when you’re at your best mentally, and to perform your best you need to be prepared in such a way. Be mindful, it is not about the number that the level is, it is about what that number is doing!
- Making insulin decisions. Timing of insulin is one thing, but also consider the duration and type of activity you are to take on in thinking whether or not to take any insulin reductions. On an insulin pump, for example, you have an added flexibility in not only being able to suspend temp basal insulin doses during your activity (which might be convenient if going for a 30 minute to 1 hour jog in the park or for a cardio session in the gym), but you can also adjust the percentage rate of insulin to maintain a background of insulin in a more suited way to your specific activity. Again in the higher intensity / longer duration activities that I do, such as running long to ultra distances, and being on MDI, an area to consider is having not only potential reductions to the basal insulin dose in comparison to the average day, but also reducing my meal time bolus doses of insulin. Another potential decision for aerobic activity is, if starting early, to potentially ‘fast’ in exercising before the morning meal and morning insulin dose. This should balance levels for at least a solid hour of exercise without having to carb or correct.
- Hydration and preparing the body. It isn’t just about the diabetes, to be at your best you have to treat your body in the best way. A lack of sleep, for example, gives stress to the body when you wake up and you both mentally and physically will feel the impact, and this will potentially interfere in how you perform. With diabetes, the stress will also impact blood glucose levels too. Hydration is similar, the body depends on it. So a key tip in prep is to maintain a good balance of hydration and solid levels of sleep.”
Paula Chinchilla from Costa Rica has lived with type 1 diabetes for 21 years and is also a certified diabetes dietitian working for the NHS in the United Kingdom. She explains in the following video about how to manage type 1 diabetes when you do sports, combining knowledge of your own body when doing sports with nutritional advice.
The most important advice Paula gives about sports nutrition and type 1 diabetes is the following:
- Consider the exercise characteristics as type (anaerobic and anaerobic), duration, frequency, time and your physical condition to decide on insulin adjustments and carb extras.
- Use simple carbs such as gels, glucose tablets, energy drinks or juice when your blood glucose levels are low before, during or after exercising.
- Have a snack with protein after exercising and before sleeping such as milk, yogurt or a sandwich.
- Use complex carbs (slower acting such as bars) when you want to maintain the glucose levels before, during or after exercising.
- Consider your levels before exercising to decide whether you need a snack and how much carbs you need to take.
- Record your blood glucose levels, adjustments and characteristics of the exercise you do to find patterns, where over time you get to a point where you can control levels whilst feeling more secure in doing exercise.
- Consider if you need supplementation with the help of a dietitian. It is not always necessary as you can achieve your energy and macronutrient (carbs, proteins and fats) requirements with food most of the time. If not, certain supplements are safe for people with type 1 diabetes with no complications.
- FIND THE SPORT THAT YOU LIKE AND ENJOY IT! DIABETES WILL NOT STOP YOU FROM REACHING YOUR GOALS
John Pemberton, RD, is a paediatric diabetes dietitian at Birmingham Children’s Hospital, and like Paula, also lives with type 1 diabetes having been diagnosed in 2008. John shares a diabetes and exercise plan:
Aim to eat a meal or snack about 1-4 hours before training or competition, depending on your schedule.
Your carbohydrate intake at this meal should be a minimum 1g/ kg body weight.
Carbohydrate aim pre exercise ______g
Examples of pre exercise meals and snacks
• Breakfast cereal & low fat milk
• Crumpets or toast + jam or honey
• Beans on toast
• Rice pudding (low fat)
• Spaghetti with tomato or low fat sauce
• Baked potato with low fat filling
• Fruit smoothies ( made with yogurt)
Carbohydrate during exercise ( “exercise carbs”)
For all exercise that lasts longer than 1 hour, you should consume some carbohydrate. Your carbohydrate needs will vary with the type and intensity of the exercise.
When you do high intensity/anaerobic exercise you may need to have your exercise carbs at the end of the exercise, rather than during.
Exercise snacks – nutritional guide
The amount of snack you need during your activity will vary, you need to look at the labels to check your snacks. Look at portion size and amount per portion as well as per 100g.
Avoid high fat snacks during exercise.
The amount of carbohydrate you need will depend on your activity and the duration. You will have a specific plan for each activity.
Carbohydrate after exercise –recovery foods
After exercise you need
To allow your muscles to “recover”. This means replacing the carbohydrate stores (muscle and liver glycogen) that have been used, repairing and rebuilding muscle tissue and replacing the water that is lost from the body.
Carbohydrate aims post exercise = 1g per kg body weight
Post exercise carbohydrate aim is _______g
You should try to eat within an hour of finishing your exercise. This may mean taking food with you in your kit bag to eat at the end of a training session.
Recovery foods should also contain carbohydrate and 10 –20g protein (see later).
After exercise recovery snacks
Make low fat choices – you need to make sure that you choose low fat foods so you do not end up eating too many calories. Examples:
• Milk shakes— make your own recovery drink with 500ml low fat milk plus milk shake powder and 25g skimmed milk powder
(e.g. marvel) Or use a bought milk shake
• 500ml fruit smoothies made with yogurt
• 60g breakfast cereal with 150-200ml low fat milk
• 2 slices bread as sandwich with cheese, meat or chicken filling and a large piece of fruit
• 300ml milk shake and 35g cereal bar
• 2 crumpets and thick spread of peanut butter
• 250g baked beans on 2 slices of toast
• 250g (large) baked potato with cheese filling
• 150g thick crust pizza
Protein ___________g /day
Eating good quality protein foods is part of eating well for sport. You should try and include a variety of protein sources, have lean red & white meat, poultry, fish (try and include oily fish also), beans and pulses.
See the end of the food list for the amount of protein in different foods.
You need protein to repair and build muscles and tissues. To increase your muscle mass, strength and power you need resistance training coupled with good nutrition.
Training should increase muscle size or strength if adequate nutrition is provided to fuel and recover from the exercise.
To improve strength and muscle mass you need to;
• Consume sufficient energy (kcals) to meet the demands of the training.
• Eat an appropriate amount of protein. To use protein for building muscles you need to be getting enough energy from carbohydrate foods to meet the energy cost of your exercise.
• Use the food lists at the end of the booklet to ensure you are getting enough protein per day.
Types of Exercise:
John Pemberton continues with explaining: “the type of exercise you do will affect your blood glucose differently.”
Anaerobic Exercise is high intensity activity which uses mainly muscle glycogen to produce ATP. Anaerobic exercise is usually performed for short periods of time, and requires all out effort.
- Weight lifting
- Some motions during basketball, football, netball and racket sports
Anaerobic exercise which only lasts for a short period (e.g. Sprinting, javelin, shot-put) will often produce an increase in blood glucose. Any exercise that includes short burst of all out effort may also increase blood glucose.
Aerobic exercise is lower intensity at one pace and relies more on blood glucose that comes from liver glycogen and/or carbohydrate intake.
Aerobic exercise will generally lower blood glucose both during and after the activity.
Gavin Griffiths adds: “one great way to measure it is by your heart rate. We all know, and feel, that when we begin exercise our heart-rate begins to increase. This is also an example of how you have to customise the preparations and outcomes of blood glucose to your body; those who are active on a more regular basis may not have quite a sharp heart-rate rise as those who do not exercise as often. When I go for a jog, my heart rate increases, but it soon stabilises to this new slightly increased rhythm of a beat as I go… whereas, when I put in a sudden burst of a sprint, the heart rate beats all the more intensely; you feel this from your breath to your heart pumping away. During those high-intensity moments of exercise, where the blood is pumping, the stimulus to release glucose from the liver exceeds glucose utilisation causing a rise in arterial glucose. In English: this means that the liver can react to that intensity and release stored glucose to the bloodstream, spiking levels upwards during activity. On the contrary, the prolonged activity such as in most forms of aerobic exercise, where the heart rate increases but only slightly, and maintains an steady pulse, the liver’s stored glycogen nears depletion, lowering your levels where the prospects of hypoglycaemia become more likely – meaning you need to fuel yourself up!”
John Pemberton RD shares: “Mixed energy system exercise: Some sports will be a mixture of anaerobic and aerobic exercise e.g. basketball, tennis, football, netball.
The mixed energy system sports will sometimes cause a rise in blood glucose, and other times a drop during the activity. This will depend on the number of high intensity bursts during the activity. Blood glucose will usually drop after the activity, as the muscles & liver replace their glycogen store from blood glucose.”
An insight shared in a past Diathlete interview from Worcester Warriors legend & England-capped Rugby Union player, Chris Pennell, who has lived with type 1 diabetes for 15 years:
CP: “My prep for game doesn’t vary too much from most of the other players. I like to eat similar things on game days so there’s no surprises to deal with! Going into the warm up I tend to be around 6-7 in old money. I actually then inject before kick off as the adrenaline from the match makes me shoot up quickly. 2 units before the game and 1 at half time keeps me between 7-10 for the match.
Post game, I get some food quite quickly. As I’ve got insulin in my system already and with my body wanting to replenish, its really key to have carbs going in. I will keep a closer eye on my blood glucose than usual just to avoid any hypos.
I would probably say your diabetes is very personal to you. Getting to know your diabetes through lots of testing is key and it really doesn’t have to stop you in life. The one thing through sport I have discovered is how much easier it is to control when you lead an active lifestyle.”
Why do a cool down? Explained by Francesca Annan BSc (Hons) MSc RD, paediatric diabetes dietitian of University College London Hospital, who runs weekly exercise and diabetes clinics.
Lactate & Glucose
During anaerobic exercise Lactate is produced in muscles.
- High lactate levels in muscles can cause delayed onset muscle soreness.
- It can also raise glucose levels because – when you stop exercise – lactate is moved from muscle to the liver.
- The Liver converts lactate back to glucose which is released into the blood.
- A cool down reduces the amount of lactate that needs to be converted to glucose
Any activity that has included anaerobic energy production should be followed by a cool down to help manage glucose levels. This can make managing diabetes easier and reduce the need for correction doses of insulin. 10-15minutes gentle aerobic exercise/stretching can really help glucose management plus it may reduce injury risk and improve performance for the next training session.
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