Doctor breaks down the science of longevity

DISCLAIMER: This article is based on information from the public domain and/or the experts we spoke to. Always consult your health practitioner before starting any routine.

Walking also featured prominently. Dr Kumar wrote, “Walking ~11 MET-hours/week (roughly 25-30 km at a brisk pace) cuts all-cause mortality risk by ~11%.” He noted, “Pace matters too; the fastest walkers have a 43% lower mortality risk than the slowest walkers.” His takeaway was, “Speed is more important than distance, but both help.”

On daily movement, he wrote, “People averaging 7,000+ steps/day have a 50-70% lower mortality risk than those under 7,000.” He also stated, “Every extra 1,000 steps/day is associated with ~15% lower all-cause mortality risk (up to a point).” His broader point was, “10,000 is not magic, but 7,000- 10,000 is a very well-supported” target.

Strength training was another part of his longevity advice. “Just 60 minutes/week of resistance training is linked to a 27% lower risk of all-cause mortality,” he wrote, adding, “That is about two short sessions per week. More is not necessarily better; the benefit plateaus.”

Sleep and work were also highlighted. Dr Kumar wrote, “7 hours is the mortality sweet spot.” He noted that “Sleeping <5 hours/night is linked to a 40% higher risk of all-cause mortality vs. 7 hours.” He also stressed, “Both too little AND too much sleep raise risk; it is a U-shaped curve, not “more is better.”

On long working hours, he wrote, “Working 55+ hours/week vs. 35-40 hours is linked to 35% higher stroke risk and 17% higher risk of dying from heart disease.” He added, “WHO/ILO estimate 745,000 deaths/year globally are attributable to overwork.” His blunt conclusion was, “No job is worth this trade.”

Finally, Dr Kumar described cardiorespiratory fitness as an especially important marker, writing, “Cardiorespiratory fitness (VO2 max) is one of the single strongest predictors of longevity in all of medical literature; stronger than most individual habits above.” He added, “Good news is that running, walking, and steps are literally how you build it.” He ended on a note against perfectionism: “None of this requires perfection.” His final advice was, “Move most days; lift twice a week; sleep 7+ hours and avoid overworking.”

These figures may sound compelling, but associations between particular habits and longevity do not necessarily mean that one behaviour directly causes a specific reduction in mortality. An expert can help put the numbers into context and explain what they mean for an ordinary person trying to build sustainable habits.

How strong is the evidence on activity and longevity?

Dr Palleti Siva Karthik Reddy, MBBS, MD General Medicine FAIG, Consultant Physician at Elite Care Clinic, tells indianexpress.com, “The evidence is quite strong that regular physical activity is associated with lower all-cause mortality and a lower risk of cardiovascular disease. Importantly, the relationship is not an all-or-nothing phenomenon. Benefits begin even at relatively modest levels of activity, and the greatest gains are often seen when an inactive person becomes moderately active. Targets such as 7,000 to 10,000 steps are useful benchmarks, but they should not be treated as biological thresholds.”

The Science of Living Longer
Lifestyle habits backed by hard data on longevity.
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Similarly, Dr Reddy adds, resistance training does not need to involve 60 minutes at a time to be beneficial. Consistency matters more than chasing a particular number. For someone who is sedentary, starting with regular walking, gradually increasing daily movement and adding strength exercises two or more times a week can produce meaningful health benefits. The goal should be to progressively build fitness rather than suddenly adopt an intensive routine.

How do sleep and long working hours affect health?

Sleep is a fundamental period of physiological recovery, and chronic sleep deprivation affects several systems simultaneously.

“Persistently inadequate sleep can increase sympathetic nervous system activity, raise cortisol levels, impair glucose regulation and appetite control, and contribute to higher blood pressure and inflammation. Over time, these changes can increase cardiovascular and metabolic risk. Consistently working 55 or more hours a week can compound these effects because long working hours often mean less sleep, less physical activity, poorer dietary choices and prolonged psychological stress. The important point is that sleep duration has a U-shaped relationship with health in many observational studies. Both very short and consistently very long sleep durations are associated with higher mortality, although excessive sleep can also be a marker of underlying illness rather than simply a cause. What matters clinically is adequate, regular and restorative sleep within the context of overall health,” states Dr Reddy.

What does VO2 max reveal about health and longevity?

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DISCLAIMER: This article is based on information from the public domain and/or the experts we spoke to. Always consult your health practitioner before starting any routine.