Bettering Me

Tag: sleep

  • “Vitality Span” Is a Marketing Term. What Matters Is Whether You’re Losing 2% of Your Aerobic Capacity Per Year

    Written by

    Unpaid Intern

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    “Vitality span” is one of those terms that sounds meaningful and means nothing. It has no standard definition, no validated measurement protocol, and no clinical utility. It is a marketing tool designed to sell programs, supplements, and subscriptions by making you feel like you are missing something that a product can provide. The concept it gestures toward is real – the difference between living longer and living well – but the packaging obscures the actual mechanism.

    The mechanism is VO2 max.

    VO2 max – the maximum rate at which your body can utilize oxygen during intense exercise – is the single most robust predictor of all-cause mortality in middle-aged and older adults, outperforming every blood biomarker in head-to-head comparisons [1]. The Baltimore Longitudinal Study of Aging demonstrated that the decline begins earlier than most people realize: VO2 max declines approximately 10% per decade after age 30 in sedentary individuals, and the rate of decline accelerates after age 50 [2]. This decline is not optional in the sense that you can prevent it entirely. It is a biological consequence of aging – reduced maximal heart rate, reduced stroke volume, reduced mitochondrial density, reduced capillary density in skeletal muscle, and reduced oxygen extraction by working muscles.

    What is optional is the starting point and the rate of decline.

    A person who reaches age 40 with a VO2 max of 45 mL/kg/min – roughly the 50th percentile for a 40-year-old man – and loses 10% per decade will reach approximately 36 mL/kg/min at age 60 and approximately 29 mL/kg/min at age 70. A person who starts at 35 mL/kg/min – roughly the 20th percentile – will be at 28 mL/kg/min at 60, a level at which simple activities of daily living (walking up stairs, carrying groceries, walking at a moderate pace) begin to require a significant percentage of maximal capacity [1]. Above approximately 30 mL/kg/min, activities of daily living are metabolically comfortable. Below that threshold, the same activities become demanding, fatigue-inducing, and eventually impossible.

    This is the concept that “vitality span” is trying to capture but fails to define: the threshold below which your aerobic capacity limits your freedom. It is not an abstract concept. It is a specific number that you can measure, track, and improve.

    The physiology of VO2 max has two components. The central component is the heart’s ability to deliver oxygenated blood – determined by maximal cardiac output (stroke volume × heart rate). The peripheral component is the muscle’s ability to extract and use that oxygen – determined by mitochondrial density, capillary density, and oxidative enzyme activity. Zone 2 training improves both components, but its primary effect is peripheral: it increases mitochondrial biogenesis and capillary density, improving the muscles’ ability to use oxygen rather than the heart’s ability to deliver it [3]. This is why Zone 2 is the foundation and HIIT is the polish – HIIT improves central function (maximal stroke volume and heart rate) but requires the peripheral base that Zone 2 builds.

    For a 45-year-old who did not build a high aerobic ceiling in their 20s and 30s, the intervention window is not closed, but the strategy changes. Zone 2 training at approximately 65-75% of max heart rate (the “conversational pace” where you can speak in full sentences but not comfortably sing) for 150-200 minutes per week has been shown to improve VO2 max by 10-15% in previously sedentary middle-aged adults over 12-16 weeks [3]. The gains are smaller than what a 25-year-old would achieve with the same protocol, but they are real and clinically meaningful. A 10% improvement in VO2 max at age 45 translates to approximately 5-7 additional years before you cross the functional dependence threshold.

    What does this look like in practice? Three to four sessions per week, each 40-50 minutes at conversational pace. A stationary bike, rower, incline treadmill, or outdoor flat walk. Heart rate at 130-150 bpm for most people (specific range depends on age and resting heart rate). The pace should feel “comfortably hard” – you could sustain it for hours but you would not want to. This is not a race. It is a base-building protocol.

    The question “are you healthy for 40” is the wrong question. The question is “what ceiling did you build in your 20s and 30s” – because that ceiling determines where you land in your 60s and 70s, regardless of what you do now. If you did not build that ceiling, start building it now. The window is narrower, but it is not closed.

    Bettering Me’s position: vitality span is a marketing term. VO2 max ceiling is a physiological fact. Track the ceiling. Build it while the window remains open.

    A note on testing. The gold standard is a maximal cardiopulmonary exercise test (CPET) with gas exchange measurement – a ramp protocol on a treadmill or bike to volitional exhaustion, with a mask collecting expired gases. This costs $200-400 and provides true VO2 max, ventilatory thresholds (VT1 and VT2), and heart rate zones. The practical alternative is a submaximal estimated VO2 max from a 1-mile walk test (Rockport test), a 12-minute Cooper test, or an estimated value from a device like Garmin or Apple Watch. These estimates have a 10-15% error margin but are good enough for trend tracking. If you can afford a CPET once at baseline and then use estimated tests annually, that is the optimal approach.

    Disclaimer: This post is for inspiration and education, not medical advice. Everyone’s body is different, so please check with your doctor before changing your diet, exercise, or lifestyle routine. By using these tips, you agree to do so at your own risk.

    References

    [1] Myers J, et al. "Exercise capacity and mortality among men referred for exercise testing." *NEJM*. 2002;346(11):793-801.. DOI: https://doi.org/10.1056/NEJMoa011858

    [2] Fleg JL, et al. "Accelerated longitudinal decline of aerobic capacity in healthy older adults." *Circulation*. 2005;112(5):674-682.. DOI: https://doi.org/10.1161/CIRCULATIONAHA.105.545459

    [3] Earnest CP, Blair SN, Church TS. "Age progression of the association of maximal oxygen consumption with all-cause mortality." *Med Sci Sports Exerc*. 2014;46(3):536-542.. DOI: https://doi.org/10.1249/MSS.0b013e3182a76c38

  • Frameworks Come and Go. The Three Non-Negotiables Are Sleep, Strength, and Aerobic Base

    Written by

    Unpaid Intern

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    Every longevity framework – regardless of the brand, the price tag, the celebrity endorsement, or the proprietary protocol name – collapses to the same three anchors when you strip the marketing layer. The seven-step morning routine becomes consistent wake timing. The custom supplement stack becomes adequate protein intake. The biohacking protocol becomes resistance training. The fancy endurance program becomes aerobic volume above 150 minutes per week.

    Frameworks differentiate themselves because differentiation is the business model. But biology does not care about differentiation. Biology responds to the same inputs regardless of the brand name.

    The first non-negotiable is consistent sleep timing, not just sleep duration.

    The circadian system does not care about your weekend sleep-in. Sleep midpoint variability of more than 60 minutes across the week – meaning your bedtime shifts by more than an hour between work nights and weekends – is associated with worse metabolic health, higher inflammatory markers, poorer cognitive performance, and increased cardiovascular risk, independent of total sleep time [1]. A person who sleeps 7.5 hours but whose bedtime varies by 90 minutes has worse metabolic outcomes than a person who sleeps 7 hours with a consistent bedtime.

    The mechanism is circadian disruption. The suprachiasmatic nucleus – the brain’s master clock – synchronizes peripheral clocks in the liver, muscle, adipose tissue, and pancreas. When sleep timing shifts, these peripheral clocks desynchronize, producing a state of internal jet lag even when total sleep time is adequate. The liver expects food at certain times relative to the sleep-wake cycle. When the sleep window shifts, the liver’s metabolic enzyme expression desynchronizes from feeding timing, producing impaired glucose tolerance, altered lipid metabolism, and increased inflammatory signaling.

    Consistent sleep timing means going to bed within 30 minutes of the same time, seven days a week. It does not mean never staying up late – it means that if you stay up late on Friday, you wake up at your usual time on Saturday rather than sleeping in. The circadian system resets through morning light exposure, not through catch-up sleep.

    The second non-negotiable is resistance training at mechanical load.

    Muscle mass is the single tissue that determines functional independence in later life. The preservation signal requires mechanical tension – load above 70% of your one-rep maximum – not calisthenics, not yoga, not walking. Two sessions per week at sufficient load produces the maintenance signal that prevents sarcopenia [2].

    “Mechanical load” means different things for different body parts. For lower body: squats, deadlifts, lunges, or leg press at a weight that makes the last two reps of each set genuinely hard. For upper body pushing: bench press, overhead press, or push-ups with added weight. For upper body pulling: rows, pull-ups, or lat pulldowns. For core: any exercise that loads the spine under tension (deadlifts, farmer carries, weighted planks) rather than spinal flexion under load (crunches).

    The minimum effective dose is two sessions per week, three sets per major movement pattern, 6-12 reps per set at 70-80% of 1RM. That is approximately 60-75 minutes per week of resistance training. Below that, you are not preserving muscle. You are exercising.

    The third non-negotiable is aerobic volume above 150 minutes per week.

    The dose-response relationship between aerobic exercise volume and cardiovascular mortality risk reduction is one of the most robust findings in exercise epidemiology. The plateau begins around 150 minutes per week of moderate-intensity aerobic activity, and the benefit continues to accumulate up to approximately 300 minutes per week [3]. Below 150 minutes, the cardiovascular risk reduction is present but significantly smaller. Above 300 minutes, the marginal benefit diminishes.

    “Moderate intensity” means approximately 65-75% of max heart rate, or a 3-4 on the 10-point perceived exertion scale – the pace at which you can speak in full sentences but not comfortably sing. This is Zone 2 training. It does not need to be running. Cycling, swimming, rowing, incline walking, or any sustained rhythmic activity at the appropriate heart rate zone qualifies.

    The sequencing matters. Sleep first because it governs the hormonal and circadian architecture that determines whether strength training and aerobic work produce adaptations. Strength second because it preserves the tissue that determines functional independence. Aerobic third because cardiovascular mortality is the primary killer, but a person with adequate muscle mass and poor cardiovascular fitness has a better survival trajectory than the reverse.

    Counterpoint: what about nutrition? Nutrition is not a separate pillar – it is embedded in all three. Sleep timing determines eating timing (the feeding window). Resistance training requires adequate protein intake (1.6 g/kg minimum) to produce the preservation signal. Aerobic training requires adequate carbohydrate availability for sustained output. There is no meaningful health framework in which nutrition is a fourth independent factor – it is the fuel and building material for the three non-negotiables. Eating whole foods, adequate protein, and aligning feeding with circadian timing is the nutritional expression of the three pillars, not a separate protocol.

    Bettering Me’s framework is not a framework. It is a sequence. Fix sleep timing first. Build strength second. Accumulate aerobic volume third. Do these three things for six months before spending a single dollar on anything else. Frameworks come and go because they need to differentiate themselves from the last framework. The three non-negotiables do not change because they are not products. They are biology.

    Disclaimer: This post is for inspiration and education, not medical advice. Everyone’s body is different, so please check with your doctor before changing your diet, exercise, or lifestyle routine. By using these tips, you agree to do so at your own risk.

    References

    [1] Fekedulegn D, et al. "Sleep timing variability and health." *Sleep*. 2020;43(6):zsz289.. DOI: https://doi.org/10.1093/sleep/zsz289

    [2] Hughes DC, Ellefsen S, Baar K. "Adaptations to Endurance and Strength Training." *Cold Spring Harb Perspect Med*. 2018;8(6):a029799.. DOI: https://doi.org/10.1101/cshperspect.a029799

    [3] Warburton DER, Bredin SSD. "Health benefits of physical activity: a systematic review." *Curr Opin Cardiol*. 2017;32(5):541-556.. DOI: https://doi.org/10.1097/HCO.0000000000000437

  • Most Sleep Data Is Interpreted Backward – The Number That Matters Is Sleep Timing Consistency

    Written by

    Unpaid Intern

    –

    Consumer sleep trackers have created a generation of people who believe they know how well they slept based on a number their wrist reported in the morning. The number is often wrong. And the number that actually matters is the one most people ignore.

    The core problem with wearable sleep data is that consumer devices estimate sleep stages using heart rate and movement data, not brain waves. The gold standard – polysomnography (PSG) – measures brain activity directly via EEG. Consumer wearables infer sleep from secondary signals. The correlation with PSG for sleep staging is modest, and most devices systematically overestimate total sleep time and underestimate sleep latency. [1] You are not getting sleep data. You are getting motion and heart rate data that an algorithm has labeled as sleep.

    But the deeper issue is that the metric most people fixate on – total sleep time – is not the strongest predictor of how they will feel the next day. Sleep timing consistency is.

    The Sleep Regularity Index, developed by researchers at the University of Sydney, quantifies how consistent an individual’s sleep-wake schedule is from day to day. Multiple studies have shown that sleep regularity is often as strong a predictor of next-day cognitive performance as total sleep duration, and in some analyses, it is stronger. [2] A person who sleeps seven hours every night at wildly different times will have worse cognitive outcomes than a person who sleeps six and a half hours at the same time every night. Consistency compensates for duration in a way that duration cannot compensate for inconsistency.

    The mechanism is circadian disruption. The circadian system expects sleep at a predictable time. When sleep timing varies, the system never fully synchronizes. The result is that the internal clock and the behavior are out of phase – you fall asleep at different biological times even if you intend to fall asleep at the same clock time. This desynchrony degrades sleep quality independently of duration. [3]

    The intervention is straightforward: go to bed within a consistent 30-minute window every night, including weekends. The “including weekends” part is where most people fail. Social jet lag – the shift in sleep timing between weekdays and weekends – is associated with higher allostatic load, poorer metabolic health, and lower mood. The weekend lie-in that feels restorative is actually disruptive. The sleep loss from the week is better addressed by moving bedtime earlier across all days than by extending sleep on weekends alone. [3]

    Does this mean you should never sleep in? No. An occasional extension of 30-60 minutes is unlikely to produce meaningful disruption. The problem is the two-to-three-hour shift that characterizes social jet lag. The threshold for circadian disruption is crossed at about 90 minutes of bedtime variability. Below that, the system adapts. Above that, the costs accumulate.

    The practical recommendation: pick a bedtime and a wake time. Keep them within 30 minutes every day. That is the only sleep metric that matters for most people. Everything else – duration, stages, deep sleep percentage – is downstream of consistency. When consistency is in place, duration tends to self-regulate. When it is not, no amount of optimization produces reliable improvement.

    The reason this message struggles to gain traction is that it is not profitable. Wearable companies sell devices that track stages. Supplement companies sell products that claim to enhance deep sleep. The “consistency is free” message has no commercial sponsor. But the data is clear: a consistent bedtime is the single most cost-effective intervention for sleep quality. No subscription required. No device needed. Just the discipline of picking a time and honoring it. The fact that it is free does not make it less powerful. It makes it harder to believe.

    Disclaimer: This post is for inspiration and education, not medical advice. Everyone’s body is different, so please check with your doctor before changing your diet, exercise, or lifestyle routine. By using these tips, you agree to do so at your own risk.

    References

    [1] de Zambotti M, et al. Wearable sleep technology in clinical and research settings. *Sleep*, 2019. DOI: https://doi.org/10.1093/sleep/zsy231

    [2] Phillips AJK, et al. Irregular sleep/wake patterns are associated with poorer academic performance and delayed circadian and sleep/wake timing. *npj Digital Medicine*, 2017. DOI: https://doi.org/10.1038/s41746-017-0001-1

    [3] Huang T, et al. Sleep irregularity and risk of cardiovascular events: the multi-ethnic study of atherosclerosis. *Scientific Reports*, 2020. DOI: https://doi.org/10.1038/s41598-020-69764-0