# Train or Rest > Updated: 2026-05-14 · Source: https://dorsi.ai/pillars/train-or-rest The hardest question in any training plan is whether today is a training day or a recovery day. This pillar gives you decision frameworks rooted in HRV, sleep, soreness, and readiness signals. The single most consequential decision in a training program is not which exercises to do or how much weight to lift — it's whether today is a training day or a recovery day. Push through when your body is asking for rest and you accumulate fatigue, blunt adaptations, and raise your injury risk. Take it easy when you actually had the capacity to train hard and you leave progress on the table. Most fitness advice skips this entire question and just hands you a weekly template; reality is messier. This pillar walks through the readiness signals that should inform the train-or-rest decision: heart rate variability trends, resting heart rate elevation, subjective soreness, sleep quantity and architecture, life-stress load, and the simple "how do I actually feel" check that no algorithm fully replaces. We unpack the science behind each signal, explain when it's noisy versus reliable, and translate them into concrete decision rules you can apply this morning before your workout. Dorsi reads these signals automatically from your Apple Watch and tells you, in one sentence, what to do today — train as planned, modify the session, or take a recovery day. The articles in this pillar give you the underlying mental model so you understand and trust the recommendation, instead of treating Dorsi as a black box. ## FAQ ### How do I know if I should train or rest today? Read your recovery signals — HRV, resting heart rate, and sleep — alongside how you actually feel. A single low reading isn't a veto, but low HRV plus poor sleep and heavy legs is your body asking for a lighter day. Dorsi weighs these together and makes the call so you don't have to. ### Is it bad to work out on no sleep? One rough night won't undo your training, but a hard session on no sleep raises injury risk and blunts recovery. A short, lighter session — or an honest rest day — usually beats forcing a heavy one. ### Should I lift weights when I'm sick? The common guide: symptoms above the neck (mild cold, runny nose) usually mean light training is fine; symptoms below the neck (chest, fever, body aches) mean rest. When in doubt, rest is the training.