I'm trying to pinpoint why on some days I can cycle on the same stationary bike, with the same settings (saddle @ "E", handlebars height at "7"), for 20 minutes, while other days I can only cycle for 7 minutes before I have to stop due to muscle aches in my thighs.

I've been tracking variables like,

  • sleep - same amount, including deep sleep; sometimes I can cycle for 20 minutes on only 4 hours of sleep, other days I have to quit after 7 minutes despite 7 hours of sleep (in both cases the deep sleep was about 50 - 60 minutes)
  • food intake - both types of days, after dinner, which includes some carbs (though I haven't tracked the amount of carbs very precises). I could also do 20 minutes on an empty stomach in the morning
  • time of day - early afternoon, early evening or late evening don't seem to make a difference
  • hydration - did ~20 minutes while pretty dehydrated

What else could I track more precisely?

Note that I don't have sore legs afterwards, and on the days I can cycle for 20 minutes, I don't really stop due to muscle pain, but rather due to running out of breath or just beating my PR by 1 minute.

I cycle every other day, so I don't think there's risk of overtraining.

  • You make no mention of the schedule of your training. That would be helpful since you may be over-training. – rrirower Oct 5 '17 at 19:07
  • @rrirower - updated the question – Dan Dascalescu Oct 6 '17 at 22:59
  • Do you ensure you use the same saddle height each time? Too low or too high would affect performance compared to just right. – zeFrenchy Oct 9 '17 at 9:22
  • @zeFrenchy: yes, same saddle and hendlebars height, but not sure about the saddle dept (never touched it). – Dan Dascalescu Oct 11 '17 at 8:37

Dan you need to see your doctor ASAP to rule this out.

Intermittent Claudication

"If left untreated, claudication and peripheral artery disease can reduce the quality of your life and lead to potentially life-threatening complications."

This is partial obstruction of the arteries. If the obstruction dislodges this can cause a heart attack or pulmonary embolism. Your symptoms sound similar to early stages but is very treatable.


  • Hopefully it's not that... I have none of the risk factors and my cholesterol levels were just fine (albeit two years ago, I haven't screwed up my diet). Also, I only get the symptoms occasionally... still worth seeing a doctor; thanks for the advice! – Dan Dascalescu Oct 14 '17 at 7:24
  • @DanDascalescu - What you're describing can be associated with a thrombosis. A quick test (blood / ultrasound etc) can rule it out and at this point, can be easily treated. Glad to hear you're being seen! Let me know how it goes. – Mike-DHSc Oct 14 '17 at 12:00
  • 1
    My doctor and PA nurse said it's not claudication. – Dan Dascalescu Feb 16 at 21:34

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