Cycling

Using a pump, by John Richards
John Richards has provided this video to runsweet.com outlining how he copes with cycling with an insulin pump. The article following the video is also by him, covering the same subject.
Hi, let me introduce myself, my name is John Richards, and I’m here to tell you about what I’ve learned in connection with setting up my insulin pump when I’m out on my bike. I’m from Louth, Lincolnshire, 61 years-old and I started cycling seriously when I was 14. By 16 I was racing as a junior, and by 19 was a first cat. amateur riding stage races. I had no problem with diabetes in my younger days; it was not until I took an awkward fall in a cyclo-cross at the age of 39. I developed the classic diabetes symptoms; loss of weight, tiredness, and extreme thirst.
Attempts were made to treat me with tablets, but within 4 years I was on insulin, and by 2002 was using a pump. If you’re still not sure about moving to pump therapy there are lots of advantages. Better B/G control means you feel better, and just doing two injections each week, instead of 35, is a big plus.
Heart problems – atrial fibrillation to be exact – serious curtailed my cycling and 90 minutes or 20 miles was my limit. For these rides I would disconnect my pump, without significantly affecting my B/G levels.
However an ablation operation in 2006 cured my irregular heartbeat, and my need for beta blockers. I found myself able to cycle longer and further, with 3.5 hours or 50 miles being my 2007 maximum. During this time I found that I was getting home with B/G numbers in the high teens, so clearly I needed to have the pump running on my longer rides, but the question was ‘at what level ?’
I posted this query on the Q+A section of CyclingNews website, and got three positive replies, all from the USA. As a happy coincidence following this, I made contact with Dr. Gazis, at the Queen’s Medical Centre, Nottingham, who in turn told me of the work of Dr. Ian Gallen at Amersham in dealing with diabetics who wish to participate in sport.
Using my pump
A consultation with Dr. Gallen, together with dietitian Carin Hume, in March this year has put me on the right track, and it’s this knowledge I want to share. Essentially the basal rate of the pump should be reduced to 20% of normal, when you’re getting changed to go out, and reset after you have got home and showered.
I use an Accu-Check D-tron Plus pump but I’m assuming all makes and models have the facility to adjust the basal rate.
During your ride, energy levels need to be maintained to prevent a hypo, and are best provided by dextrose tablets together with a sports drink at 6% solution. I use the PowerBar product , but if you’re on a tight budget then basic glucose (picture) is a much cheaper substitute.
The only way to monitor what is going on in your body is to carry out frequent blood/glucose tests. One at the start, followed by a repeat every 30 minutes, and one at the end. If, like me, you’ve been brought up to accept that all training rides should be non-stop, this comes as a cultural shock. Worse, you can’t expect a big group to stop 4 or 5 times on a ride whilst you carry your checks, so you will either have to ride alone, or with one or two understanding friends.
I use the Accu-Chek Aviva monitor, and it together with the tin of strips and the finger pricker (picture) all fit into one jersey pocket. I usually just take six or seven strips for each ride – I’ve had the experience of dropping the open tin, and spilling a full tin all over the road. Now if you’re a better bike handler than me, then you could do the test on the move, but I wouldn’t take the risk myself, and certainly wouldn’t endorse the idea. With practice each test can be done in 40 seconds, whereas a broken hip will give you 12 weeks of pain and discomfort, as well as stopping you getting out on the bike.
The next stage is to assess the result of each test, and decide how much carbohydrate you need to take. 30 grams per hour is a good base to work from, but of course each ride is different, depending on intensity terrain and the weather, so you may need up to twice that. Dextrose is usually sold in small packets, with 14 tablets making 47 grams, so three tablets equals 10 grams.
Extra Carbs
I make up two thirds of a 500ml feeding bottle (that is, 330ml) of water with 20 grams of the PowerBar powder. This is almost all carbohydrate, so five 66ml swigs would deliver 4 grams at a time. If I get a B/G reading of between 6 and 8, I’ll have 3 tablets, washed down with a swig of the drink. If it’s less than 6, I’ll double that, and if it’s less than 4, I’ll rest for 15 minutes, eating either a couple of fig biscuits or a small banana as well as my dextrose. Remember, you’re testing and reviewing your B/G level every 30 minutes.
If the reading is 8 – 10, I’ll just swig the drink. If it’s 10-12 I’ll do nothing, but if it’s over 12 I would give myself 1 unit of insulin to move it down 2 points. Bear in mind that you’ve still got your pump connected and setting a lower basal does not stop you from giving yourself a bolus.
When you return, review your B/G as soon as possible. Providing your B/G is at least 7, you should give your body more insulin. You can either move the basal adjustment from 20% to 200% for an hour, or just reset the basal to normal, and deliver a bolus of 2 units. I prefer the latter method, it seems easier to me.
Keep on monitoring your B/G for the rest of the day, at 90-minute intervals. 6 hours after the ride finishes your body draws on glycogen to repair the muscles, and without careful watching this can lead to a hypo. If you have the Compass software for the Aviva on your computer, you can produce a graph of your whole day’s B/G activity both for yourself and your consultant.
Of course, we’re all different, so what works for me may not for you. This method does avoid horrendous hypo’s out on the road, and the after-ride lethargy that comes from hyper results. It does not get over the problem of stopping, though there is another piece of kit that does, and you may want to consider this.
You can obtain, though not on the NHS, a real-time B/G monitor, which is attached to you in much the same way as the pump. A sensor is inserted under your skin, and reads your B/G level every five minutes. A transmitter, which is stuck on your chest next to the sensor, sends the data to a monitor, which must stay within 2 metres of you. The monitor is about the size of an electronic keypad used for opening your car doors, and fits neatly into your back pocket. This, of course, can be easily read on the move, and comes with software to store all your data.
It sounds great, doesn’t it, but in my experience has several drawbacks. The sensor must be changed twice per week and is more intrusive than the pump needle. The transmitter is about the size of a match box, but feels uncomfortable after a while. The monitor must remain within 2 metres of the transmitter at all times. If you get up in the night for a pee, and forget to take the monitor with you, then you will lose the signal, and have to then run through a set up procedure which takes several minutes. Finally the equipment costs around £1500 to buy, and the sensors cost £40 each, so being fully committed to this system would be £4,000 a year in addition to the capital cost. I did a 3-day trial with the kit, and for me it was not worth pursuing the idea. Perhaps in a year or two’s time, when the hardware is both smaller and cheaper, I’ll try it again.
In the meantime I’m hoping that as I become more experienced in monitoring, I can reduce the number of tests I have to do at the roadside. Next month I’ll try 40-minute invervals, and gradually extend the gap if possible. Two tests on the road during a 3-hour ride would be a big gain for me.
Finally if you have any questions about the things I’ve mentioned, then you can email me at the Runsweet website, and I’ll do my best to provide answers.
Mark Standhaft
Mark Standhaft is a 23-year-old relatively new type 1 diabetic patient, who needed some assistance with his management of his diabetes with his cycling.

His diabetes is managed with Glargine 30 units at night and Novorapid between 22 and 26 units three times a day. Prior to the diagnosis of diabetes, as a junior, he was competing at international levels racing in Europe and he aspires to return to his previous high level of international racing, but currently he races at club level.

Mark’s exercise regime consists of almost daily intense cycling. On Monday he rests. On Tuesday’s he goes to work and in the evening he has a 2-hour race, this is usually about 6 o’clock in the evening. His blood glucose at the start of the race is typically 15, and falls down to 2 or 3 throughout the race. On Wednesday’s he goes to work and in the evening he trains for 2 hours. This consists of interal training with short bursts of high output training, followed by lower rates. This is to build up his lactate tolerance. On Thursday again he races for 2 hours in the evening and on Friday he trains for 2 hours in the evening much in the same way as Tuesdays. On Saturday mornings he trains for 4 hours starting at 10 o’clock in morning having had his breakfast at 8 o’clock in the morning and on Sunday’s he races again for 3-4 hours at about 10 o’clock having eaten his breakfast a 6 o’clock.
It is in these last 2 episodes that he finds it particularly difficult to control his blood glucose and in particular, he is finding that he has marked loss of performance during the training and has the greatest of difficulties, maintaining his blood glucose throughout the training period. Conversely after the exercise, he finds his blood glucose rises very rapidly.

As far as food is concerned, Mark did not measure the quantity of carbohydrate that he is eating, he is trying to lose weight and get his body fat down. He has 2-3 large bowls of cereals in the morning (estimated at least 100 gms of carbohydrate). He has a sandwich at lunchtime (about 90 gms), and then he has flapjacks several times throughout the day, which are approximately 30 gms. In the evening he has his main evening of again of rice, pasta or potatoes. Whilst racing he takes a glucose containing fluid and he drinks 500 mls, which is probably 30 gms of glucose during these training periods.

The problems that Mark is facing is that he has doesn’t know his total energy intake or requirements are. He needs a strategy for dealing with feeding, for rest days, training days and race days or strategies to deal with races in evening or in the morning. He is reacting to his blood glucose results rather than being proactive and his insulin regime may not be appropriate for different levels of physical activity on different days.

It is of particular note that Mark’s blood glucose falls during racing, that even though his blood glucose starts at 15 and that he takes regular carbohydrates throughout the racing, his blood glucose falls by more than 10 mls, leaving him at risk of hypoglycaemia. This is an extremely common feature of sub-maximal exercise in diabetic patients. Mark’s exercise really can be described in 2 types. His racing which would be typically at a VO2 of somewhere between 50-60%. In this exercise he is relying on muscle glycogen and blood glucose, which is sourced from the liver. However, his main fuel source would appropriately be free fatty acids and ketones bodies. One of the features of Mark’s situation is that his ability to mobilise fuel sources is reduced by excessively higher levels of insulin, hence his fatigability. He is therefore relying on glucose output from his liver to support his exercise, which is limited. During certain parts of Mark’s exercises however, his VO2 max will increase substantially. In this situation, his exercise will be limited by the fuel supply of glucose and also his ability to tolerate lactate.

Mark could use the following strategies deal with his problem. The first is to find out from either his own records or from his colleagues the total quantity of food that he needs to ingest in the day. This should then be divided up into appropriate feeding times and quantities so that we can then measure his carbohydrate intake accurately throughout the day and give his insulin doses related to that. One can estimate that Mark’s basal metabolic rate would be about 2,500 kilo calories and that approximately 1,000 kilo calories per hour with strenuous exercise, he needs his daily intake of somewhere between 4,500-5,000 calories a day. This assumes a total daily energy carbohydrate intake, if we assume 70% of his calorie intake, it should be as carbohydrate of between 700-800 gms of carbohydrate per day. Clearly the type of carbohydrate needs to be mixed in the course of the day, so that on normal working days when he is working in the evening, the carbohydrate should be given in complex forms with his breakfast and his lunch but swapped to rapidly absorbing low glycaemic index or when racing. A starting dose would be 60 gms per hour, but this may need to be increased to as much as 200 gms per hour depending on the intensity of the race. After racing, he should immediately have some further carbohydrate followed by a small dose of quick acting insulin prior to his evening meal for which he should give the further normal dose of insulin.

On days when he is racing in the morning, he should have his normal pre-race breakfast, with carbohydrate throughout the race, a post-meal snack with insulin and then his normal food. On days when he is resting he should have his normal food intake minus the extra carbohydrate intake associated with exercise.

Next we come to his insulin therapy:
Mark’s insulin therapy seems sensible at the moment; however, he needs a further small dose of insulin with snacks between breakfast and before racing in the afternoon (30 gems of carbohydrate with 6 units of Novorapid with each of these snacks). Insulin should not be taken sooner than 3 hours prior to exercise. However, on days when he is racing, cycling or training in the morning, his overnight insulin should be swapped from Glargine to Humulin I and the dose reduced by half. It is very important that he has little insulin in his system on those mornings as this will reduce his ability to mobilise free fatty acids and ketones bodies and may provoke in-race hypoglycaemia. He should however have his breakfast at least 3 hours before cycling in the morning and have half the normal insulin dose at that time, with the aim of starting the race with a blood glucose of somewhere between 10-14.
Mark's Exercise Regime
Consists of almost daily intense cycling. On Monday he rests. On Tuesday’s he goes to work and in the evening he has a 2-hour race, this is usually about 6 o’clock in the evening. His blood glucose at the start of the race is typically 15, and falls down to 2 or 3 throughout the race. On Wednesday’s he goes to work and in the evening he trains for 2 hours. This consists of interal training with short bursts of high output training, followed by lower rates. This is to build up his lactate tolerance. On Thursday again he races for 2 hours in the evening and on Friday he trains for 2 hours in the evening much in the same way as Tuesdays. On Saturday mornings he trains for 4 hours starting at 10 o’clock in morning having had his breakfast at 8 o’clock in the morning and on Sunday’s he races again for 3-4 hours at about 10 o’clock having eaten his breakfast a 6 o’clock.
It is in these last 2 episodes that he finds it particularly difficult to control his blood glucose and in particular, he is finding that he has marked loss of performance during the training and has the greatest of difficulties, maintaining his blood glucose throughout the training period. Conversely after the exercise, he finds his blood glucose rises very rapidly.
As far as food is concerned, Mark did not measure the quantity of carbohydrate that he is eating, he is trying to lose weight and get his body fat down. He has 2-3 large bowls of cereals in the morning (estimated at least 100 gms of carbohydrate). He has a sandwich at lunchtime (about 90 gms), and then he has flapjacks several times throughout the day, which are approximately 30 gms. In the evening he has his main evening of again of rice, pasta or potatoes. Whilst racing he takes a glucose containing fluid and he drinks 500 mls, which is probably 30 gms of glucose during these training periods.
The problems that Mark is facing is that he has doesn’t know his total energy intake or requirements are. He needs a strategy for dealing with feeding, for rest days, training days and race days or strategies to deal with races in evening or in the morning. He is reacting to his blood glucose results rather than being proactive and his insulin regime may not be appropriate for different levels of physical activity on different days.
It is of particular note that Mark’s blood glucose falls during racing, that even though his blood glucose starts at 15 and that he takes regular carbohydrates throughout the racing, his blood glucose falls by more than 10 mls, leaving him at risk of hypoglycaemia. This is an extremely common feature of sub-maximal exercise in diabetic patients. Mark’s exercise really can be described in 2 types. His racing which would be typically at a VO2 of somewhere between 50-60%. In this exercise he is relying on muscle glycogen and blood glucose, which is sourced from the liver. However, his main fuel source would appropriately be free fatty acids and ketones bodies. One of the features of Mark’s situation is that his ability to mobilise fuel sources is reduced by excessively higher levels of insulin, hence his fatigability. He is therefore relying on glucose output from his liver to support his exercise, which is limited. During certain parts of Mark’s exercises however, his VO2 max will increase substantially. In this situation, his exercise will be limited by the fuel supply of glucose and also his ability to tolerate lactate.
Mark could use the following strategies deal with his problem. The first is to find out from either his own records or from his colleagues the total quantity of food that he needs to ingest in the day. This should then be divided up into appropriate feeding times and quantities so that we can then measure his carbohydrate intake accurately throughout the day and give his insulin doses related to that. One can estimate that Mark’s basal metabolic rate would be about 2,500 kilo calories and that approximately 1,000 kilo calories per hour with strenuous exercise, he needs his daily intake of somewhere between 4,500-5,000 calories a day. This assumes a total daily energy carbohydrate intake, if we assume 70% of his calorie intake, it should be as carbohydrate of between 700-800 gms of carbohydrate per day. Clearly the type of carbohydrate needs to be mixed in the course of the day, so that on normal working days when he is working in the evening, the carbohydrate should be given in complex forms with his breakfast and his lunch but swapped to rapidly absorbing low glycaemic index or when racing. A starting dose would be 60 gms per hour, but this may need to be increased to as much as 200 gms per hour depending on the intensity of the race. After racing, he should immediately have some further carbohydrate followed by a small dose of quick acting insulin prior to his evening meal for which he should give the further normal dose of insulin.
On days when he is racing in the morning, he should have his normal pre-race breakfast, with carbohydrate throughout the race, a post-meal snack with insulin and then his normal food. On days when he is resting he should have his normal food intake minus the extra carbohydrate intake associated with exercise.
Next we come to his insulin therapy:
Mark’s insulin therapy seems sensible at the moment; however, he needs a further small dose of insulin with snacks between breakfast and before racing in the afternoon (30 gems of carbohydrate with 6 units of Novorapid with each of these snacks). Insulin should not be taken sooner than 3 hours prior to exercise. However, on days when he is racing, cycling or training in the morning, his overnight insulin should be swapped from Glargine to Humulin I and the dose reduced by half. It is very important that he has little insulin in his system on those mornings as this will reduce his ability to mobilise free fatty acids and ketones bodies and may provoke in-race hypoglycaemia. He should however have his breakfast at least 3 hours before cycling in the morning and have half the normal insulin dose at that time, with the aim of starting the race with a blood glucose of somewhere between 10-14.
How did the plan work out?Mark has found that things have progressed very well. He has embarked enthusiastically on these changes with really very major improvements in his performance. His level of cycling has improved so that he is now regularly in the leads of his race.
He is being very careful with his food intake and supplementing his carbohydrate intake particularly during races.
3 examples:
On a 5 hour race averaging 28 kilometres per hour over 140 km in distance, his blood glucose typically starts at 14 and drops to 11 and is maintained by taking approximately 120 gms of glucose in the form of pastilles, 100 gms flapjack and 75 gms x 2 in the forms of high 5 glucose drink.
On an evening ride of 59 km, he is cycling more quickly at 32 km/ph. His blood glucose falls from 18 to 7, although he does notice a reduction in his performance when his blood sugar is on the higher side. This is without any food supplements.
On a hilly rides, again of 5 hours, with an average speed of 28 km/ph he is maintaining his blood glucose, falling from 11-8 by taking approximately 60-80 gms of carbohydrate per hour.

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