# Heart rate slowed down during MTB race???



## markgrise (Oct 22, 2007)

I entered a race last Sunday and I'm concerned after seeing data from Strava/Garmin Connect. 

My heart rate monitor dropped to 110bpm about 30 mins into the race. I don't recall feeling like my heart was at 100bpm. In fact, it felt like it was going faster than ever before. I chalked it up to a bad battery. 

After the race, I ate a sandwich within ten minutes. It was very hard to swallow. I felt too tired to eat it. My neck was also a little weak. 

I know heart rate monitors are not always accurate, however I've never seen one have a consistent heart rate go down. Typically, here are spikes, but I be never seen prolonged periods where the heart rate goes up or down (unless it's accurate). My concern is around my heart rate being down while I felt like it was higher than ever. 

Prior to the race (days), I consumed healthy food and plenty of of water. I ate a small meal before and after the race too. 

Has anyone had anything like this happen before? I've raced a few times, but am pretty inexperienced so far.


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## markgrise (Oct 22, 2007)

Here are screen shots from my phone


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## WillTheGreat (Aug 26, 2010)

I've had this happen once, and I just assumed it was bad data. I felt strong, and my pace didn't slow so I assumed the data was just wrong.


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## man.cave (Nov 8, 2014)

Has to be skewed data, different if u was riding around with kids vs race lol

Sent from my SAMSUNG-SM-G870A using Tapatalk


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## JohnnyVV (Feb 28, 2015)

My Garmin HRM reported my untimely death routinely until I replaced the (3rd) strap with a Polar one.


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## markgrise (Oct 22, 2007)

JohnnyVV said:


> My Garmin HRM reported my untimely death routinely until I replaced the (3rd) strap with a Polar one.


Haha. I just replaced my Polar H7 for the same reason....


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## primoz (Jun 7, 2006)

With Polar it's pretty much normal when battery goes too low. You are starting to get really weird numbers, and riding really hard at 30 beats/minute is nothing unusual... well if you trust your HRM is 100% accurate  So I would say it's bad battery in transmitter. 
Not being able to eat sandwich and having neck (and everything else) "a little weak" is pretty much normal thing after race, so personally I wouldn't really worry about this. If something would be wrong with you, your HR would actually go high, not down to "easy" 110


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