Train or Rest

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.