Heart rate variability, better known as HRV, has become one of the most talked-about recovery metrics in fitness. Open almost any smartwatch app and you’ll likely find a daily score sitting alongside your sleep and resting heart rate data. Higher numbers are often presented as a sign of good recovery, while lower scores can trigger panic after a poor night’s sleep or a hard training block.

But HRV isn’t as straightforward as social media makes it seem. The number on your watch is heavily influenced by age, meaning comparisons between people are rarely useful. A score considered excellent for a 25-year-old may be entirely unrealistic for someone in their 50s or 60s.

So what actually counts as a good HRV score for your age? And why do numbers tend to decline over time?

HRV measures the variation in time between each heartbeat. Although your pulse may feel steady, the gap between beats is constantly changing by tiny amounts depending on what your nervous system is doing. Those fluctuations are controlled by the autonomic nervous system, which regulates processes such as stress response, recovery, breathing and heart rate.

According to Dr Elisabetta Burchi, clinical psychiatrist and head of research at Parasym, ‘It reflects the balance between sympathetic (fight-or-flight) and parasympathetic (rest-and-digest) activity, making it a valuable indicator of stress adaptation, cardiovascular health and recovery capacity.’

Put simply, a higher HRV is generally associated with better recovery and a greater ability to adapt to physical or psychological stress. Lower scores can occur during periods of illness, fatigue, poor sleep, high stress or accumulated training load.

HRV varies significantly between individuals, but one consistent trend across the research is that scores tend to decrease with age.

Younger adults typically have greater autonomic flexibility, meaning the nervous system can shift more efficiently between stress and recovery states. As we age, that flexibility gradually reduces, which is reflected in lower HRV values.

The following ranges provide a general benchmark for healthy men:

Source: Shaffer & Ginsberg (2017); Nunan et al. (2010)

These numbers should be treated as broad reference points rather than strict targets. According to Dr Burchi, tracking changes relative to your own baseline is far more useful than comparing your score with someone else’s.

For example, an HRV of 35 may be perfectly healthy for one person but unusually low for another, depending on age, fitness level and lifestyle.

Part of the decline comes down to changes within the autonomic nervous system itself. Ageing is associated with reduced parasympathetic nervous system activity, alongside gradual declines in cardiovascular efficiency and recovery capacity.

However, lifestyle still appears to play a major role. People who remain physically active, sleep well and manage stress effectively often maintain higher HRV scores later in life compared with more sedentary individuals.

Broadly speaking:

• HRV tends to be highest during early adulthood
• Scores often begin declining gradually through the 30s and 40s
• Recovery capacity generally decreases further after 50
• Older adults typically show lower nervous system flexibility overall

That decline is considered a normal part of ageing, not necessarily a sign that something is wrong.

HRV can fluctuate significantly from one day to the next. In many cases, temporary drops simply reflect that the body is under greater stress than usual.

Common factors associated with lower HRV include:

• Poor sleep
• Psychological stress
• Dehydration
• Illness
• Alcohol consumption
• Hard training blocks
• Inadequate recovery

Although ageing influences HRV, lifestyle habits can still affect the score significantly. Strategies linked to improved HRV include:

Importantly, improving HRV usually happens gradually. The goal shouldn’t necessarily be to chase exceptionally high numbers, but to support better recovery and long-term health.

HRV is best viewed as a tool for understanding how your body is coping with stress, training and recovery – not as a competition against other people’s smartwatch screenshots.

Kate is a fitness writer for Men’s Health UK where she contributes regular workouts, training tips and nutrition guides. She has a post graduate diploma in Sports Performance Nutrition and before joining Men’s Health she was a nutritionist, fitness writer and personal trainer with over 5k hours coaching on the gym floor. Kate has a keen interest in volunteering for animal shelters and when she isn’t lifting weights in her garden, she can be found walking her rescue dog.