How much the body had available at the end of the day. The battery fills left to right: a full battery means good reserve, a nearly empty one means very little was left. Colour shifts from green (good) through blue (building) to amber and red (low or very low). The number shown is the evening reading - the value that drives the balance score.

What was asked of the body across the day - physical, thinking, emotional, and social demand combined. The needle position shows how much. Crucially: the speedometer colour reflects whether the load was within reserve, not just how high the load was. A needle pointing to 3 in green means high load was well managed. The same needle position in red means reserve was insufficient for that load. High load is not automatically a warning - only if the colour says so.

Whether capacity improved, held steady, or declined from morning to evening.

↗ Got better - capacity improved during the day.

→ Held steady - capacity held stable from morning to evening.

↘ Got harder - capacity declined during the day. Worth noticing even on a Stable day - the body may be moving toward strain.

The arrow shows direction, not the overall state of the day.

The relationship between evening reserve and the day's load. A positive balance means the body had capacity to spare. A negative balance means load exceeded what was available. When balance is positive, the body had capacity to spare. When negative, the day asked more than was available. It is the single most important number for understanding how the day went.

A retrospective description of how the day's capacity was handled, given what was happening physiologically. It answers: given the body's state, how was the day approached? This is one of the most important learning signals - over time, the pattern shows whether protective responses are being deployed at the right time.

One of seven named outcomes assigned to each day, based on how it actually played out against recent patterns - looking at the day's relationship to what came before, not just the morning-to-evening movement captured by the arrow above. Because each day gets one of these seven outcomes, they can be counted across a week or month, so patterns become visible that a single day's narrative can't show on its own.

Usual daily activities without deliberate modification of demand - appropriate when available capacity appeared sufficient for what the day required.

Restorative activity chosen deliberately. Rest, gentle movement, or supportive routines, while keeping demand low.

A gradual, measured return to some ordinary demands with deliberate restraint maintained. May be appropriate when moving out of a crash or careful recovery, during mild immune activity, or following a period of deliberate constraint.

Deliberate withdrawal from demand. Activity significantly reduced, rest protected, and no further load added.

The day's demands exceeded what the body could sustain without a deliberate, protective response. A descriptive classification, not a judgement.

The body remained broadly steady. Symptoms and capacity did not materially worsen or improve.

Symptoms increased or capacity declined across the day. The body moved into a more strained or reactive state.

Symptoms reduced or capacity increased across the day.

The day reflects cost from prior days rather than same-day load. Typically follows a previous overextension or stacked demand.

A short-lived dip followed by a quick recovery, within the same day or by the next morning.

A recovery held steady, with no relapse and no new cost introduced.

Capacity returned with a hormonal phase shift, rather than in response to rest or reduced demand.

The body is managing well. Energy, thinking, and emotional bandwidth are holding. The data shows no signs of accumulating strain today.

Inflammatory signals are present but the body's capacity is not yet significantly impaired. A decision-point day - these days can shift toward Immune Active if demand increases before the inflammation settles, or back toward Stable if protected and well-managed. The body is working harder than the day may suggest.

The immune system is actively responding. The body's available energy and resources are being directed toward this response, which is why fatigue and sensitivity may feel higher than expected relative to what you've actually done. You may still be functioning, while the body is working very hard internally. Immune Active days typically require containment, not pushing through.

The body's reserves have been exceeded. The body is in recovery mode. Physical energy is very low, sensitivity to stimulation may be heightened, and emotional bandwidth is reduced. Recovery will likely take more than one day. These days often follow a period of accumulated demand rather than something that happened on the day itself.

The body is moving out of a crash or difficult period, but has not yet rebuilt its reserves. Capacity may feel like it is returning - and often it is - but resilience is not yet restored. These days are vulnerable to setback if demands increase prematurely. It is recommended that demands remain low and predictable to protect the recovery that is underway.

The body's available reserves have run down - through accumulated demand, immune activity, or a combination. The body is operating below its usual baseline and recovery is the priority. This may show up as waking already depleted, or as energy that drains steadily through the day - sometimes arriving 24-48 hours after the demands that caused it.

Capacity is holding well, but demand has been running high relative to that capacity and the margin between the two is narrowing. Not a difficult day on its own - but worth noticing, since it often comes before one.

A hormonal event - cycle phase shift, peri-menopausal transition, or vasomotor symptoms (hot flushes, night sweats, palpitations) - is the main driver of capacity today. Recovery comes with the hormonal phase change, not through rest alone. This distinguishes these days from depletion or crash, where rest is the primary support.

The nervous system is under sustained pressure. Recovery signals may be blunted and the body is less able to adapt to demand. Symptoms such as palpitations, heat sensitivity, elevated resting heart rate, or poor HRV recovery may be more noticeable. Low activity, attention to hydration, and reducing time spent upright are often helpful on these days.

Function is limited by musculoskeletal pain, structural restriction, or joint instability. The key distinguishing feature: emotional energy and thinking bandwidth are typically preserved - which distinguishes these days from states like Crash Day or Depleted where the whole system is affected.

Mechanical Constraint appears alongside a primary state, not instead of one - shown as a second coloured pill in the diary. For some conditions (hypermobility, connective tissue disorders, arthritis), it may be the dominant daily reality rather than a secondary note.

The period phase. Capacity is often lower, immune sensitivity higher, and the body is managing significant hormonal and physical activity. Rest and low demands are most supportive. Crashes and difficult days landing in this phase are not coincidental - they reflect the compounding of existing load with the body's hormonal demands.

Energy typically rises as oestrogen builds. This is often the best recovery window of the cycle - the phase where rest can do the most work. A good window for careful re-introduction of demands, but not for catching up on everything avoided during the harder phases.

Peak energy and capacity for most people. A brief window - typically the best three days of the cycle. Worth protecting rather than over-spending. For those with fluctuating health conditions, stable days clustering here are a meaningful signal to track across cycles.

Progesterone rises and energy is often sustained in early luteal, but begins to reduce as the phase progresses. Immune reactivity can increase. This is a phase of gradual change rather than sudden shift - the body is beginning its preparation for the next cycle.

The late luteal phase. Capacity reduces, symptoms may amplify, and the immune response is often more reactive. Existing conditions frequently flare more easily in this window. Immune Active days in this phase are not random - they reflect the hormonal context. Resolution comes with the phase shift, not through pushing through.

For irregular or peri-menopausal cycles, PHIT tracks hormonal events as they happen rather than calculating phase by day number - because day number becomes unreliable when cycle length is unpredictable. Night sweats, hot flushes, unexpected bleeds, and mood shifts are captured as events, and patterns are identified retrospectively from what those events correlate with in the capacity data.

Rest and minimal demand are most supportive right now. Physical, thinking, and social demands should all be reduced where possible.

On Hormonal Phase Limitation days, recovery follows the hormonal cycle rather than the usual rest-and-recover pattern. Rest supports the body through the phase, but cannot speed it up. The aim is to reduce demand while the phase runs its course.

Low, consistent demand. The goal is stability. Gentle movement is fine and often helpful. Avoid spikes or variability.

Recovery is underway - protecting it is worthwhile. Low-demand, restorative activity is recommended. The aim is calm, not challenge.

Capacity appears sufficient for a careful increase in demand. Delayed effects remain possible - increase gradually and observe the body's response over 24-48 hours.

Yesterday's strain may or may not have settled overnight. Check how the body feels before deciding how much the day can hold. If yesterday's effort doesn't feel resolved, ease back rather than resuming as usual. If it feels clear, proceed as normal, but watch for any return of strain through the day.

No particular restriction seems indicated based on today's picture and recent patterns.

Reducing time spent upright may help the nervous system recover. Prioritise horizontal rest where possible, stay well hydrated, and keep activity gentle and brief.