[doughywilson]

I have noticed that my heart rate stays much lower on runs in the morning vs evening. When I run in the evenings, my heart rate is much more variable and spikes easier. I’ve logged a lot of data and have confirmed this through dozens of test runs. The question is why? Anyone else noticed this and have an explanation?

Topic

[Dada]

Dada on September 9, 2019 at 9:40 pm #28187

I would suggest that your stress level is totally different. When I look at my Garmin stress levels in the morning it’s fairly low so my parasympathetic nervous system is in the lead. At night, through a stressful job my sympathetic nervous system is in the lead. This causes higher heart rate I suggest.

BR
Dada

[Anonymous]

Anonymous on September 10, 2019 at 9:12 am #28201

@doughywilson: I don’t know the reason, but I’m the same way. In the morning, I’m good to go. Between 1 and 3, I’m dead to the world. Between 3 and 6, I can do light recovery workouts. And others are the opposite.

@dada: I wouldn’t put much faith in Garmin’s (or Suunto’s or Fitbit’s or whoever’s) recovery “metrics”. They’re all based on generic formulas, an imperfect model (HRV), and calculated off of bad data (wrist-based, optical heart rate monitors). They’re just sciency gimmicks that help sell watches.

[doughywilson]

doughywilson on September 10, 2019 at 10:48 am #28210

Thanks for the comments Dada and Scott. The follow-up question is if it’s better to train during these lower-heart-rate times for the best aerobic training, or if it’s better to train when heart rate bounces around easily. I’ve noticed that I’m able to push much harder in the morning and my heart rate will not spike a lot even though I know I am exerting a bit more. But I’m not sure if that means I’m going into zone 3 and my heart rate just doesn’t reflect it, or if it means my body is more efficient in zone 2 during those times.

[Dada]

Dada on September 10, 2019 at 9:03 pm #28233

Scott:

I’m sorry but the autonomous nervous system is the main driver in heart rate variability, heartrate and blood pressure. No second guessing here.

See i.e. https://www.google.com/url?sa=t&source=web&rct=j&url=https://pdfs.semanticscholar.org/2d83/2c6742573614e7c0febeaebdb82a57782015.pdf&ved=2ahUKEwi-u6yq4cfkAhWqq1kKHSJ7BvwQFjAQegQIARAB&usg=AOvVaw2W6hbAQmICMi0k203i–se&cshid=1568170287701

https://www.google.com/url?sa=t&source=web&rct=j&url=https://pdfs.semanticscholar.org/2d83/2c6742573614e7c0febeaebdb82a57782015.pdf&ved=2ahUKEwi-u6yq4cfkAhWqq1kKHSJ7BvwQFjAQegQIARAB&usg=AOvVaw2W6hbAQmICMi0k203i–se&cshid=1568170287701

@doughywilson:

I have the same problem. I’d rather go for the afternoon workout since I have to run way harder in the morning to get my heartrate up. Muscular fatigue is probably higher that way.

Dada

[Anonymous]

Anonymous on September 12, 2019 at 1:21 pm #28334

@dada: Sure, but that doesn’t mean that a wrist-based optical monitor can accurately measure it; or the vendors’ software can interpret it accurately for an individual; or that there aren’t better things to pay attention to when it comes to effective training.

[Anonymous]

Anonymous on September 12, 2019 at 1:22 pm #28335

@doughywilson: I would train when it feels best. Based on your description, I suspect that’ll be in the morning.