US Open Tennis

[C&E Guy]

Just watching it on SKY and saw German player Zverev injecting himself during a break.

We Googled him and he is a Type 1 who has to inject himself during matches.

Correct me if I’m wrong but surely playing a strenuous 5-set Grand Slam tennis match would reduce his blood glucose a lot. So why does he need to take insulin? That would surely cause him to hypo.

Surely he should be taking extra glucose.

 

[Robin]

Maybe a sport such as tennis doesn’t provide a particularly constant aerobic sort of exercise that drops your blood glucose. Sudden bursts of energy followed by a rest period between serves/games may cause an anaerobic response, which can result in the liver dumping glucose in a 'fight or flight' reaction, and sends the Bgs up not down. (He may have to watch his levels overnight, which is when the body normally recovers from this liver output, and replenishes it, causing hypos)

 

[Martin.A]

My understanding is that while gentle exercise can reduce BG, strenuous exercise increases it. Tennis must count as strenuous exercise, especially at the level he plays.

 

[Chelseagirl]

He eats a lot of carbs before the match too. Read about it during Wimbledon. As do a lot of diabetic elite sports people. Couldn’t see him scanning or checking his phone though so I didn’t know how he knew to inject without doing bloods.

 

[AndBreathe]

He eats a lot of carbs before the match too. Read about it during Wimbledon. As do a lot of diabetic elite sports people. Couldn’t see him scanning or checking his phone though so I didn’t know how he knew to inject without doing bloods.

During Wimbledon, I saw him finger prick test.

 

[helli]

It is no where near as simple as exercise causes BG to fall or even “strenuous exercise” causes BG to rise (what is “strenuous exercise”? For a start).
Things like stress and duration of continuous exercise has a big impact.
Stop - start activities such as HIIT (high intensity interval training) causes BG to rise, not because it is “strenuous” but because (as my simplistic not medical mind understands) the liver starts to release glucose every time you start an interval. A tennis match will be like this - you are not constantly running around a track, you stop and restart after each point.
Add the stress of performing in a world class tournament and I am not surprised the player needs insulin top ups during the game.

 

[helli]

He eats a lot of carbs before the match too. Read about it during Wimbledon. As do a lot of diabetic elite sports people. Couldn’t see him scanning or checking his phone though so I didn’t know how he knew to inject without doing bloods.

Probably experience. He has played many tennis matches so will know in advance that he needs a top up after, for example, the first set.
That said, he may have a CGM reporting to his watch or something else the camera did not catch.
I am not an elite athlete but I know I need an additional bolus after an hour of climbing.