CGM Readings while playing tennis - Apple Watch?

My daughter plays tennis in college and wears a Dexcom G5 and Omnipod. She right can access her CGM information through her Apple phone or the Dexcom receiver. When she is on the courts, she loses connection to her receiver or phone. Would an Apple Watch eliminate the lost connection issue while she is playing or does it just relay information from the iPhone. There is wifi availability on the courts if that makes a difference. Tennis only allows a few seconds during changeovers and it would be a great benefit if she did not have to prick her fingers in the limited time available.

Currently using Dexcom provided equipment and applications, it requires a relay from the iPhone to the Watch.

Do you have the old or new Dexcom Receiver? The new Dexcom Receiver and the Dexcom App running on the iPhone both have a 3-hr data backfill. This potentially can be useful playing sports. However when the transmitter comes back in range, it can take anywhere from a couple seconds to a full 5 minutes to get the data dump and backfill the cgm graph.

It sounds like with Tennis, you would not have enough time to ensure the data dump and often the cgm would not have enough time to backfill the data. If the Receiver / iPhone are left back in the seats and well out of range.

However, would you be able to leave the iPhone and/or the new Receiver with one of the Judges? Is there a line judge behind your daughter? That would likely be close enough to allow the connection to mostly pick up while she is playing. Then between sets, she would be able to look at the device which should already have the data.

If the iPhone was sitting with the line judge and your daughter had a Watch, there is a good chance the connection would be adequate for the Transmitter to go from your daughter to the iPhone by the Judge. Then for the data to be relayed back to the Watch with your daughter.

wifi is not relevant for these types of connections.


You need the phone inbetween, for a while at least, since Dex is working on a watch only solution.
The phone can be kept in the bag next to the bench, no? In that case there is no issue, there are no obstacles between the transmitter and phone, i.e. between the phone and the watch. The advantage is that she can get the readings directly on the wrist, without digging after the phone.

If you are worried about the Dex getting hit by/smashed by a tennis ball close to the court, I’ve had good luck with these storage boxes. Waterproof, protective storage box

Thanks for the reply. She is a new user so she has the latest receiver. She has her phone and receiver next to her tennis bag which is on a chair or bench near a net post. This past weekend she had four matches and she lost connectivity to both the phone and receiver while she was playing. As you noted, she only has 90 seconds during switchovers so it is always a challenge to check your blood, consume carbs and water in the time allowed. I was hoping the Apple Watch would take away one of the steps but it sounds like that will have to wait until the watch can connect directly to the receiver.

By “latest receiver”, do you mean the touchscreen receiver?

Thanks for the reply. Her movement around the court takes her out of the range at least based on play this last weekend,

Have you considered strapping the receiver to her arm or in a fabric belt like the ones they sell for pumps. That way you wouldn’t have to mess with the phone or lose connection.

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Thanks for taking the time to respond. She generates too much velocity with her arms to have anything strapped to her arm. She once tried to insert her omnipods on her arm and that turned out to be a very bad idea when it went flying off during a match but it was a great idea to suggest.

Yes it is a touchscreen receiver. It shipped to her in January

The belt I was talking about is an actual belt you wear around your waist under your clothes and although I have never used one I would think it would be pretty hard to dislodge.

I use a G5 and don’t have a receiver. The iPhone / iWatch combinations seems to work well for me to keep an eye on my sugars while mountain biking / road cycling. For mountain biking, I just keep the phone in my backpack, and for road cycling I keep it in my jersey pocket. But, those are obviously not going to be good solutions for your daughter.

When at home, I don’t carry my phone around. Our house is 75’ long and I normally leave my phone on the counter at about the half-way point. So, I’m always within about 30 feet of the phone and it always works.

If your daughter left the iPhone on the side of the court, it would pick up the signal from the Dexcom transmitter. The iPhone would easily transmit back to the iWatch.

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Would anything as discussed in the following post be something that might work for you in terms of a direct transmitter to watch connection?
@doc77 would be able to speak further on how that works.

Dexcom sent me an elastic belt about 6 months ago, holds a receiver around my waist. It works great. I wore the G5 receiver around my waist playing ice hockey, under the pads. Never had a problem with it slipping around or getting dislodged. It would be pretty easy for a tennis player to unzip the belt, glance and check the BG, and zip it back closed between games and possibly between points as long as it was easily accessible under a shirt.

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If a belt sounds unappealing, she could also consider tucking the receiver in a tight sports bra and using an Apple Watch to view numbers. I’m not sure how big the new model is, but I think the old one could comfortably be worn there.

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Currently the Apple Watch is required to relay from the iPhone.

Good call. I should’ve said phone.

I am a tennis player and I used to use the Enlite CGM. Didn’t work for me for the reasons you stated. I have been using the Freestyle Libre for about a year now. It doesn’t alert me if I am getting low, but I do check it pretty much every changover. If you are not familiar with this, look into it. All you do is hover a scanning device over the sensor and it gives you a reading and a graph showing if your numbers are going up or down. By the way, I do put it on the back of my arm, but I do use an extra piece of tape over the sensor to make sure it stays in place.

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I am a club tennis player and play in a [competitive] league [for old fogies]. I am a new Dexcom G5 user and have an Apple watch (version 3) and an iPhone 8. I have not had a problem with connectivity between my phone and watch on the court while playing matches (I’ve usually left my phone sitting on top of my bag so there’s a visible line to me). Sometimes I’ll have the three dashes (—) on my watch, but if you touch on them, it will connect over to the phone and pick up the latest glucose. All of that said, I’m anxiously awaiting the upgrade where the transmitter sends directly to the watch. It’s just a hassle to have to have the phone in the middle. Good luck to your daughter! Jessica

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Thanks everyone for your input. I did get my daughter an apple watch. Today she had her first match with it which was cut short due to the east coast storm. She only lost connection once and that was for about a minute or so. She did crash during the match and it was nice not to have to prick herself in the short time allowed. Also getting a 76 with a side arrow is very different form a BG reading of 76 without the current trend. Next match is Thursday and hopefully it will work as well as tocay