Heart Rate Variability and Training Load in a Masters Runner
A 47-year-old runner trains for half marathons and wears a chest-strap monitor. Her resting heart rate has risen from 48 to 56 beats per minute over 9 days, and her heart-rate variability has dropped about 15 percent below her 8-week baseline. She reports sleeping 5.5 hours per night during a work deadline and rates her legs as 'heavy' on easy runs. Her weekly volume has been steady at 45 km, but she added a second interval session 10 days ago. She has a 10 km race in 6 days and asks whether to do one more hard interval session this week to sharpen up.
1. Interpret the resting heart rate and heart-rate variability changes in the context of her recent training and life stress.
Read the worked answer
Resting heart rate up about 8 beats and HRV down about 15 percent from baseline, sustained over 9 days, point to accumulated fatigue and incomplete recovery, not to a fitness gain.
The timing is telling: the change coincides with a second weekly interval session and a period of 5.5-hour sleep. Both are added stressors, and the autonomic markers are responding to the combined load. Heavy legs on easy runs support the same conclusion.
Caveats to state: a single day's HRV is noisy, and a 15 percent drop over 9 days is more meaningful than any single reading. Resting heart rate can also be elevated by heat, illness, or alcohol. A reasonable interpretation is that she is in a functionally overreached state that is still reversible with a few easy days, rather than overtrained, which would require weeks to months of underperformance.
The practical reading: the body is signaling that recovery is the limiting factor this week, not training stimulus.
2. Given the race in 6 days, decide whether she should add the hard interval session and justify your plan for the week.
Read the worked answer
She should not add another hard interval session. The goal of race week is to arrive fresh, and the markers say she is not currently fresh.
Plan for the 6 days:
- Days 1-3: Easy running at conversational pace, 25-35 minutes, plus one short session of 4-6 x 20-second strides to keep neuromuscular sharpness without accumulating fatigue.
- Day 4: Rest or very light mobility work.
- Day 5: Short easy jog of 15-20 minutes with 2-3 short pickups at race pace, no more than 30 seconds each.
- Day 6: Race.
Rationale: fitness is built over weeks and cannot be added in 6 days, but fatigue can be shed in that window. The second weekly interval session is the likely driver of the current state, so it should be removed now and reconsidered only after the race, when sleep normalizes and resting heart rate returns toward 48. If resting heart rate is still elevated on race morning, she should adjust race pace expectations rather than force the original goal.