People often say they feel stressed but it doesn’t necessarily mean they’re literally suffering the psychological and physical effects of stress. These can include an increased risk of depression, anxiety, impaired immunity, and cardiovascular and metabolic health problems.

The flip side is that some people may not feel stressed but their bodies are affected nonetheless.

Research suggests that one way of objectively measuring an individual’s resilience to, or risk of, stress-related illness is heart rate variability or HRV.

HRV, which describes how the time interval between heartbeats varies, is emerging as a clinical approach to assessing and treating the unseen physiological impact of chronic stress. Our body is constantly reacting to demand and change to maintain stable and optimal health.

When we feel threatened, a cascade of chemicals (adrenaline is the best-known example) prepare the body for defence by influencing the cardiovascular system to adjust to the threat. That’s the sympathetic nervous system at work. As we relax and our blood pressure and pulse begins to slow, it’s the parasympathetic nervous system taking over.

So HRV changes depending on whether the sympathetic or parasympathetic nervous system dominates our heart rate and it’s the difference between the rates that provide information about how our bodies are responding to stress.

Increasing resilience

An assessment of heart rate variability can be achieved with a five-minute ECG recording. Armed with this information and the results of a discussion with the patient about the stressors in their life, a doctor can then recommend a management plan to help reduce stress.

A later repeat of the testing can check whether the management plan is working and helps to provide the patient with a way of increasing resilience to future stressful episodes.

It’s an approach that’s being used to help elite athletes make decisions about their training workloads.

Athletes are subject to huge amounts of physical stress in the training they perform. Too much training (stress) and inadequate recovery leads to ‘over-training’, which is associated with impaired performance, a reduction in wellbeing and energy, and an increased risk of injury.

Rather than asking “How do you feel?”, HRV reflects the resilience of an athlete’s nervous system and provides useful information for planning subsequent training.

It’s not just athletes who are using this technique either. In the corporate world, HRV is being used by some organisations to help identify stress being felt by workers at all levels of an organisation due to increasing workloads and tight deadlines.

Although still a relatively new concept, HRV testing is one of many techniques in the stress management realm that may help improve health, and it has the potential to improve work satisfaction and productivity.