There are a couple of diabetes related things that happen when we exercise
- our liver releases glucose to give us energy
- our bodies become more efficient at using insulin
In an ideal world, during exercise, these two should cancel each other out. But, after 3 months, you’ve probably realised our diabetes doesn’t always follow the rules.
Whether exercise causes our BG to go up or down depends on quite a few things - how much bolus (fast acting) insulin we have active in our body, how fit we are, how long we exercise for, what type of exercise we do and what our BG is when we start.
I try to minimise the amount of insulin I have active by not having any fast acting insulin 3 or 4 hours before exercise. For me, this means limited eating ... or only nuts before exercise.
Starting BG is important because, too low and I am at risk or hypo and too high, I la k energy so trying to exercise can push my BG up higher.
I assume you are injecting (I use a pump which changes things). If so, I agree with
@Knikki that about 8mmol/l is a good starting point.
The fitter I am at a sport, the less impact it has on my BG. As a result, the affect of that exercise on my BG may change over time.
In general, short spurts if exercise will push your BG up. So HIIT often leads to a high.
Resistance exercise, like weights, will also push BG up.
Typically, cardio (over 20 minutes or more) will usually lower BG.
However, if you are used to running on a flat treadmill and decide to run up a steep hill on a wet windy day, the stress may lead to a high BG.
I participate in,a number of sports and need to manage my BG differently for each of them
- for climbing I need extra insulin as the resistance of carrying my body weight, the short routes and the stress of feeling scared will raise my BG
- my gym sessions are a combination of weights and cardio. As a result, one balances the other. If I start the gym with a highish BG, I will start with 30 minutes of cardio (which will,lower my BG), if I start the gym with a lower BG, I will start with weights to raise my BG.
- running usually lowers my BG. As I have a pump, I manage this by reducing my basal. When I was injecting, I would drink weak fruit squash drink instead of water on my run. The advantage of squash over energy drinks (apart from the cost) is you can adjust the sugar content to suit your needs.
The impact of football on your BG depends on the type of game you play. If you are on the go non stop, your BG is likely to rise. However, if you are a goalie, for example, you will have short moments of heavy activity followed by quite pretty moments so your BG may rise.
The only time I eat without injecting is to increase my BG to a target level. I have not missed an injection because I will be exercising.
The other thing to consider is the 24 to 48 hours after exercise. As I mentioned above, exercise causes our liver to release glucose. As a result, outer glucose supplies are reduced so we have less to drip constantly. This may lead to lower BG over the next day or so.
I used to lower my basal for the next 24 hours. Some say a change of basalntakes 3 to 4 days to bed in so this would have no impact. But it worked for me.
Sorry for the long essay. I think the key points (TLDR) are
- you need to find the optimum BG to start exercise
- be aware (and try to minimise) insulin on board
- we are all different and so we need to test a our BG a lot to find out what works for us
- be prepare for low BG up to 48 hours after exercise
- keep fast acting glucose close to hand
- tell your team mates
Finally, this may sounds a bit daunting but don’t be put off: Gary Mabbut, StevevRedgrave and Henry Slade have not been... and nor have
@Knikki and I.