Tools · Move
Should I train today?
Five questions, against your own normal, and one of four answers. The same check px runs for you before you wake.
Today
Train as planned.
Your signals sit at your normal. This is the day the plan was written for: if a hard session is on it, go and do it properly.
Educational, not medical advice. If you have diabetes, a heart condition or another medical condition, ask your doctor or a dietitian first.
How it works.
Three signals answer the question, read together and against your own normal: heart rate variability (HRV), resting heart rate and last night’s sleep. Your own fourteen-day normal is what counts, not anyone else’s numbers.
Each signal can lie on its own. One low HRV morning is noise. Resting heart rate three or more beats above normal is a reason to ease off. Sleep is the exception: five to six hours switches the session whatever the other two say, and under five makes it a day for easy movement or rest. Two context questions sit underneath: how hard the last three days were, and whether something specific hurts. A pain that changes how you move outranks every number.
The answer is almost never “skip”. It is “adjust”, in either direction. HRV-guided training studies find that fitting hard days to readiness does at least as well as a fixed plan, because the hard days land when the body can use them.
px runs this check every morning from your wearable, with your calendar and food alongside it, and tells you why.
Sources
- Plews DJ, Laursen PB, Stanley J, Kilding AE, Buchheit M. Training adaptation and heart rate variability in elite endurance athletes: opening the door to effective monitoring. Sports Med. 2013;43(9):773–781.
- Javaloyes A, Sarabia JM, Lamberts RP, Moya-Ramon M. Training prescription guided by heart-rate variability in cycling. Int J Sports Physiol Perform. 2019;14(1):23–32.
- Granero-Gallegos A, González-Quílez A, Plews D, Carrasco-Poyatos M. HRV-based training for improving VO2max in endurance athletes: a systematic review with meta-analysis. Int J Environ Res Public Health. 2020;17(21):7999.
- Fullagar HH, Skorski S, Duffield R, et al. Sleep and athletic performance: the effects of sleep loss on exercise performance, and physiological and cognitive responses to exercise. Sports Med. 2015;45(2):161–186.
From px Insights
Should I Train Today? How to Decide Before You Start
Not sure whether to train or rest? Here is how to read sleep, HRV and resting heart rate together and make the call in under a minute, before you get changed.
Do I Need a Rest Day? How to Tell Tired From Overtrained
Tired is a feeling. Under-recovered is a state, and your signals can tell them apart. When a rest day earns its place, and what to do with it.
Training on Empty: How to Adjust When You Have Barely Slept
Four hours of sleep and a session on the plan. Skip it, push through, or adjust? How to size the day to the night you actually had.
Questions
Should I train if my HRV is low?
One low morning on its own, usually yes. HRV moves with sleep, alcohol, heat and stress. If it is low for several days, or low alongside a raised resting heart rate or short sleep, take the intensity down or switch to easy aerobic work.
Should I train after a bad night’s sleep?
Usually yes, but not hard. Under six hours, swap intervals or a heavy lift for easy aerobic work or technique, and move the hard session a day or two. One short night does far less harm than people fear. A run of them is different.
Is it better to skip a session or do a shorter one?
Almost always shorter. Thirty honest minutes at the right intensity keeps the habit and most of the benefit. Skipping outright costs momentum.
Should I train when I feel ill?
Not with a fever, chest symptoms or aches all over: rest, and see a doctor if it does not settle. This check is for ordinary days and does not replace medical advice.
Tomorrow morning, already decided.
Seven days free. By this time next week, px knows your normal.