Exercise Raising Blood Glucose - Type 2

Hi all,
I’ve been noticing that my blood sugars are getting really high when I play tennis. I played the other day with my husband and felt horrible the whole time and when I tested my blood sugar afterwords I was right around 160, which is very high for me. That time I figured that it was because it was a singles game and a very strenuous workout, which apparently can trigger your liver to dump glucose into your blood. But tonight I played doubles, which is only a moderately strenuous workout. When I started I was at 140, 1 hour later I was at 147 and after another hour I was at about 170 - YIKES! I think it’s because of the adrenaline of the tennis match causing some sort of stress response in my liver. Do you have any thoughts or recommendations of how to keep my blood sugar lower during high intensity tennis matches (or moderate intensity for that matter)

To give you some background: I maintain an A1C around 6.1 and I aim for 140 or under 2 hours after each meal. I control via diet, exercise (so I thought) and metformin 2/day. I’d love some suggestions on how to keep it lower during tennis matches. Thanks!


More common for T1s to go high after strenuous exercise. I’ve gone up way higher than 30 pts, followed by lows hours later. Yep, it’s adrenaline. Even if you don’t feel stressed, it’s a stress response.

I’m T1 & start out a bit high to try to prevent liver glycogen dumping, but not helpful to you since you began at 140.

Drinking water during can help, Dehydration, even slight, causes high BG.

I am diagnosed as a type 2, but suspect I have some insulin deficiency. I weight train and my blood sugar can rise markedly, over 200 mg/dl. Some of this can be the stress hormones as Gerri points out, particularly for a competitive game like tennis or in weight training where there is exertion. Some of it can also be complicated by low insulin levels and your liver dumping blood sugar to restore energy levels. As long as your blood sugar returns to normal range within an hour or so after exercise, I would just not worry about it. If you continue to have highs after exercise, then you can worry about it. In my case, I’ll sometimes still be over 200 mg/dl an hour after exercise and it will take hours to come down. As a type 2, you will likely find that some post workout nutrition, a protein shake with milk or a power bar can help restore your blood sugars after exercise.

+1 on what they said. I get that occassionaly too more often w/ harder workouts. try not to stress about it. in the long run it’s good for you

Im a type 2. I also do 40 minute cardio exercises a day…and will have elevated blood sugar within the 30 minute after exercising. Often attributed to stress hormones…specially if one plays competitively. I can go as high as 130 to 150. But will slowly decrease within the hour. Often some trainers recommend some sort of relaxing exercises after…light stretching and deep breathing to gradually decrease your heartbeat. . Indeed, drinking water can help a lot.

Hi Stacey

I am also a tennis player. The other day we were having a luncheon after tennis so I decided I should check before eating. I don’t normally test after exercise. I was 110 when I started and 180 when I finished. The same thing happens in the gym especially if I exercise more than 1 hour. I was told it was due to stress hormones and that my body interprets competiitve exercise as stress and signals liver to produce more glucose. Just what I need. My doctor says don’t worry. But I play a lot of tennis and do lots of workout in the gym. I think my HbA1c is higher because of it.

Well, at least we know we’re not alone. But it is frustrating, isn’t it…

Not that anything is ever fair, but it’s aggravating that exercising as we’re supposed to do sends BG up. I’ve opted for more moderate exercise. I hate seeing those highs.

I play alot of tennis, 4 times a week during the winter, and during the spring and summer, I will often play everyday, and sometimes twice a day. When I was first diagnosed years ago, I worried that I would go low playing tennis, so I checked my BG’s before, during, and after tennis, and was really surprised to find that it would go up playing tennis. So now I don’t worry about lows during tennis, as I will usually start at 85-100 and will rise to 140-150 after playing, but two hours after, will be back down to normal. My A1c is consistently 5.7-5.9.

My last HbA1c was 5.9, although most of my numbers are in the low 100’s except for a few higher fasting bgs. I wonder if the temporary spike accounts for the higher HbA1c. Whenever I ask my doctor, he says not to worry becaus exercise is so good. Of course, he is also a tennis player. I don’t ever test during the match so I wonder at what point I spike. Sometimes I do try to bring something small and low carb to eat in between sets. That helps a little.

I just started exercising again. But just mostly on bike for 30 mintues. I notice mine goes up too - not much since it is not too strenuous but I was surprised as I though it was supposed to go down also. A diabetic nurse said it is due to the muscles storing sugar and they are being released - I think that was what she said - don’t know if this is correct - but she also said not to worry about it. In my case, I could see this as making sense because I haven’t been using many of muscles for a while and they are getting reused again. But I could definatley see the stress aspect of it too.

I guess yoga might be the best exercise since it is supposed to be stress relieving and relaxing. :slight_smile:

I am glad I am not alone though - I was worried about that.

The muscles store glycogen, which is stored glucose so when you exercise you use up that glycogen. When that is used up your pancreas produces glucagon which is a hormone which then signals liver to produce more glucose. This is a counter regulatory hormone to make sure we don’t go too low. I also think different stress hormones are produced which raise bgs. I find no rhyme or reason for the spikes some time. I have started bringing a low carb snack like nuts to the gym or tennis courts. Every 30 minutes or so I will grab a few. I find the process of eating something small forces a Phase 1 insulin respone which counters the glucose. I am still working on the perfect snack. I’m in the process of making my own protein bars, since the ones they sell have too many artificial ingredients and sugar alcohols. If anyone has ideas let me know.