Real-time stamina is designed to help guide you toward your best possible performance, empowering you to push your limits with confidence. You gain context for interpreting feedback from your body, and you experience valuable insight along the way. Time and distance to exhaustion estimates predict what you can expect to achieve with your remaining stamina at your current effort.
Stamina describes your capacity for good, quality performance. Running out of stamina means reaching or rapidly approaching the point where keeping up becomes a serious struggle. How hard you are working affects how quickly your stamina drains during an activity.
Stamina (0–100%) reflects how much you have left in the tank at your current level of effort. This perspective combines general fatigue with more temporary limitations imposed by anaerobically driven efforts such as sprints, climbs and attacks.
Potential Stamina (0–100%) focuses specifically on the effects of broader, longer-lasting fatigue contributors such as muscle cell damage, central nervous system fatigue and carbohydrate (glycogen) depletion. Activities that result in near or total depletion of your potential stamina typically require several days of recovery before you are back at full capacity.
If you haven’t fully recovered from your last activity, your potential will not be at 100%.
Expect your stamina and potential to align during sustained moderate-intensity efforts. Up the intensity, exceed your lactate threshold (running) or FTP (cycling), and stamina will drain faster than your potential. Return to a moderate, sustainable effort, and stamina will gradually replenish toward your potential as the residual effects of high-intensity, anerobic exertion begin to wear off.
Calculating Stamina
Real-time stamina tracking works by combining your physiological metrics with a multi-layered analysis of your recent and longer-term activity history. This includes examining training durations, distances covered, training load accumulations and load distributions for meaningful patterns that reflect fatigue resistance and personal tolerances for aerobic and anaerobic exercise.
While general fitness levels provide some insight into your performance ability, activity-specific training adaptations substantially influence your capacity for sustained performance. In other words, running ability doesn’t directly translate into cycling ability and vice versa. As a result, real-time stamina estimates are primarily guided by running history data during running activities and cycling history data during cycling activities.
