Biometric markers
Wearable and body-composition data that often predicts risk before bloodwork changes.
Key takeaways
- VO2 max is among the strongest single predictors of longevity available, and it is trainable.
- HRV is individual. Your trend against your own baseline is the signal.
- Visceral fat and waist-to-height ratio outperform BMI for metabolic risk.
- Wearable screening features can flag likely sleep apnea, but a diagnostic AHI still requires a home sleep test or lab polysomnography.
Tracked through wearables, fitness testing, and body composition assessment rather than blood draws. Some of the most predictive health data available comes from continuous monitoring rather than a single blood panel. Baseline integrates wearable data from Whoop, Oura, Garmin, and Apple Watch.
HRV (Heart Rate Variability). The variation in time between consecutive heartbeats. One of the most sensitive continuous indicators of recovery status, stress load, and sleep quality. A declining trend often shows up before illness, overtraining, or burnout. Standard: highly individual, trend matters more than the absolute number. Optimal: stable or improving trend. Moved by: sleep quality, stress management, alcohol reduction, consistent aerobic training, cold exposure.
Resting Heart Rate. A simple but powerful longevity marker. Each 10 bpm reduction is associated with meaningfully lower cardiovascular risk. Rises with deconditioning, chronic stress, and metabolic dysfunction, and improves with aerobic fitness. Standard: under 100 bpm. Optimal: under 60 bpm, elite athletes often 40 to 50 bpm. Moved by: Zone 2 cardio, sleep quality, stress management, metabolic health optimization.
Sleep, Total Duration. The primary recovery and repair window for the body. Chronic short sleep under 7 hours is independently associated with cardiovascular disease, obesity, cognitive decline, and immune suppression, regardless of other health behaviors. Standard: 7 to 9 hours (adults). Optimal: 7.5 to 9 hours with adequate deep and REM distribution. Moved by: sleep hygiene, circadian alignment, alcohol elimination, GH secretagogue protocols supporting deep sleep architecture.
Deep Sleep. The stage where growth hormone is predominantly released and cellular repair occurs. It is also when the glymphatic system drains, flushing metabolic waste out of the brain through cerebrospinal fluid, a clearance process that only runs properly during deep sleep. Declines with age, alcohol use, and fragmented sleep. Standard: roughly 1 to 2 hours per night. Optimal: 20 to 25% of total sleep time. Moved by: alcohol elimination, consistent sleep schedule, GH peptide protocols, temperature-optimized sleep environment.
REM Sleep. Essential for memory consolidation, emotional regulation, and cognitive performance. Suppression is strongly associated with mood disorders, anxiety, and faster cognitive aging. Standard: roughly 1.5 to 2 hours per night. Optimal: 20 to 25% of total sleep time. Moved by: alcohol and cannabis elimination, consistent sleep schedule, stress management.
Sleep Apnea Screening (AHI). The apnea-hypopnea index counts breathing interruptions per hour of sleep. This is the piece a standard fitness wearable cannot measure and is the main reason dedicated sleep testing matters, not just tracking hours in bed. Standard: under 5 events per hour is considered normal. Optimal: under 5 events per hour, confirmed by testing rather than estimated. Moved by: weight management, sleep position, evaluation and treatment by a provider if elevated.
VO2 Max. The maximum rate the body can use oxygen during exercise. One of the strongest single predictors of longevity and cardiovascular health available. Declines about 1% per year after 30 without intervention. Standard: age and sex adjusted norms (average 35 to 40 mL/kg/min for adults). Optimal: upper quartile for your age and sex. Moved by: Zone 2 cardio (3 to 5 hours/week), high intensity interval training, consistent aerobic base building.
BMI (Body Mass Index). A crude but widely used proxy for body composition. Does not distinguish fat mass from lean mass, which limits its clinical value. Used only as a starting reference point, body composition assessment provides the meaningful data. Being underweight in older adults carries its own frailty risk, so lower is not automatically better here. Standard: 18.5 to 24.9. Optimal: 22 to 24.9, the longevity sweet spot. Moved by: addressed through metabolic protocols, GLP-1 therapy, resistance training, and nutrition.
Body Fat Percentage. A far more clinically relevant metric than BMI. Excess fat, particularly visceral fat, drives insulin resistance, systemic inflammation, and hormonal dysfunction. Standard: men 10 to 25%, women 18 to 32% (varies by age). Optimal: men 12 to 18%, women 20 to 26%, lean mass preserved. Moved by: GLP-1 therapy, resistance training, protein optimization, caloric deficit, assessed via DEXA scan for accuracy.
Visceral Fat. Fat stored around internal organs, the metabolically active tissue most directly tied to cardiovascular disease, insulin resistance, and systemic inflammation. More important than total body fat for metabolic risk. Standard: rating 1 to 9 on most consumer devices. Optimal: rating 1 to 5, confirmed by DEXA for accuracy. Moved by: GLP-1 therapy, Zone 2 cardio, reduced refined carbohydrate intake, metabolic protocol.
Waist-to-Height Ratio. A simple, highly predictive measure of central body fat. More useful than waist circumference alone because it accounts for height. Ratios above 0.5 are linked to higher cardiometabolic risk across all body types. Standard: under 0.5. Optimal: under 0.45. Moved by: metabolic protocols, targeted fat loss strategies, GLP-1 therapy, resistance training.
What this means for you
Continuous data from a wearable, read as trends rather than daily scores, often flags a problem months before a blood panel does.