The science of stress

Unless you are completely new to the topic of workplace wellbeing, you will probably already know that mental health has a significant role to play. Poor mental health is consistently one of the most common reasons for sickness and absence from the workplace and is a significant focus for many organisations. As mental health is defined by the World Health Organization as “a state of mental wellbeing that enables people to cope with the stresses of life”, this article will examine the following key points:

• What is stress and resilience?
• How to recognise the signs and symptoms of stress
• The links between physical, emotional and mental resilience
• Techniques for managing energy.

Photograph: iStock/jacoblund

What is stress?

As with many things in the world of workplace wellbeing, there are various definitions for the word ‘stress’. The reported ‘founder of stress theory’, Hans Selye, described stress as “the non-specific response of the body to any demand for change”. In his research, Hans showed how the immune system can become suppressed when a stressor is present for long enough. What is a stressor you may ask? Well, it has been suggested that a person experiences stress when a perceived demand exceeds that person’s coping abilities – so perception has a big role to play.

If we use the example of public speaking, some people find this an energising, positive, fulfilling experience, whereas others might shy away from such an experience. Even though the stressor (public speaking) is the same thing to both, the perception of it differs. So, if a demand for change could result in stress and the perception of the demand for change has a role to play, how might we respond to stress to ensure it doesn’t negatively impact our immunity?

What is resilience?

Resilience is the capacity to prepare for, recover from and adapt to stress, challenge or adversity. Although many of the stressors we experience in life may be unexpected and out of our control, one thing is for certain: we will all experience stress at some point. In some cases, we may not have sufficient resilience to prevent the stress, challenge or adversity from negatively impacting our immune system.

You can think of resilience as being like a rechargeable battery. In the same way that stress may drain the resilience battery down, we can learn to build our resilience capacity and sustain our energy. To better understand how to do this, we must first consider the underlying physiology behind our stress response.

The physiology of stress

Within our bodies, we have our central nervous system (CNS), which consists of the brain and spinal cord, and is responsible for almost everything the body does. The brain governs how we think, learn, move and feel and the spinal cord carries the messages between the brain and the rest of the body.

If you imagine the CNS to be the trunk of a tree, one of the branches of the CNS is the autonomic nervous system (ANS), which is responsible for regulating things outside of our active control, such as heart rate, blood pressure, breathingand digestion. If you then imagine the ANS branches off into two smaller branches, they are: the sympathetic nervous system (SNS) and the parasympathetic nervous system (PSNS). The SNS is more commonly referred to as the fight-or-flight response whereas the PSNS can be referred to as the rest-or-digest response.

Among other things, the SNS is responsible for slowing salivary secretion, speeding up heart rate and inhibiting digestion. In conflict with this is the PSNS as it is responsible for increasing salivary secretion, slowing down heart rate and facilitating digestion.

The incredible thing about these nervous systems is that there isn’t a simple on and off switch, which means they are constantly monitoring which system should be most active. And it’s because of this, that two opposing nervous systems influence heart rate, that we are able to measure the physiological phenomenon – heart rate variability (HRV), which is the very small-time differences between each heartbeat (as shown in the images below).

You may be wondering what relevance this information has? Well, a good amount of HRV is associated with good physiological resilience, whereas a low HRV is associated with lower immunity and impaired brain function. So, if we can identify the factors that improve the balance of our HRV, we may be in a position to better equip our bodies with the physical resilience needed to manage physical energy and stress.

Lifestyle factors that impact resilience

Knowing that certain lifestyle choices can improve or worsen our HRV means we are better able to charge our resilience battery to respond to challenge, stress or adversity. The list below outlines some of the lifestyle factors that may result in a lower HRV, and therefore if present over a period of time, could result in negative health outcomes:

• Low physical fitness
• Excess caffeine intake (individual tolerance applies)
• Excess alcohol intake
• Smoking (tobacco)
• Insufficient antioxidant intake (from natural food sources)
• Excess sugar intake (more specifically processed sugar)
• Muscular pain (that can be managed through specific stretching or strengthening)
• Poor quality sleep
• Insufficient relaxation activities
• Insufficient breaks at work.

Although this is interesting information, it doesn’t mean that if someone is physically fit, eats and sleeps well, and takes appropriate rest and breaks that they won’t experience stress. But it does mean than if someone is experiencing any kind of stress, that if they reduce their exercise, make less healthy food/drink choices, and don’t take sufficient recovery, that they are at an increased risk of the stress having an adverse effect on their health rather than it being absorbed by their resilience battery.

Marcus Herbert is head of wellbeing at British Safety Council. Photograph: British Safety Council

Recognising the signs of stress

Now we know the physiology behind the stress response, we can start to consider what might be some of the physical signs and symptoms. It could be said that effective stress management begins by recognising the signs, which may include:

• Heart beating faster
• Dry mouth
• Digestive problems
• Lightheaded when standing
• Shoulder tension
• Disrupted sleep or change in sleep patterns
• Erratic behaviour – for example, road rage
• Using alcohol or drugs to cope.

Of course, the signs listed above are not solely linked to stress – for example, someone might feel lightheaded when standing because they might naturally have a lower blood pressure, or someone might have digestive problems due to an intolerance to a certain food.

That said, the signs listed may occur in someone experiencing stress simply because of the SNS being more active than the PSNS and therefore resulting in a lower HRV. By knowing what the signs of low HRV are, we may be more in-tune with our bodies and able to notice that we need time to recover.

For example, if someone notices their sleep patterns start to change and they finish the working day with shoulder tension, they can take a moment to consider if they are feeling stressed and they can make any lifestyle changes to build their physiological resilience.

Lifestyle to manage pressure

To know what lifestyle choices we can make to improve the balance in our HRV, we simply need to think back to the lifestyle choices that result in a higher activation of the SNS.

One of the most cardio-protective things we can do is be sufficiently physically active each week in order to maintain a good level of physical fitness. We do not necessarily need to keep active as if we were training for a sporting event (although there would of course be health benefits to that). There is a dose-response relationship with exercise but not in a linear fashion – i.e. it isn’t as simple as the more we do, the more fit we become. In fact, doing a small amount in comparison to none at all has a bigger impact than doing a small amount to a high amount of physical activity.

Photograph: iStock/fizkes

The recommended amount of physical activity to yield sufficient benefits is to be moving for 2.5 hours at a moderate intensity every week. This doesn’t need to be in one go and it would be better to spread it across the week. A moderate intensity would be at a perceived effort between six to seven out of 10 (with 10 being the hardest you could work). It would be wise to exercise gently in the evening and avoid high intensity (>7/10 effort) exercise before bed, so activities such as Tai Chi, Pilates and resistance training (weightlifting) would be advisable.

Avoiding high intensity exercise before bed is important because raising the heart rate to a very high level may result in the release of a hormone called cortisol, which is often referred to as the ‘stress-hormone’ but maybe unfairly so. Cortisol is not a stress-inducing hormone – rather it is a hormone that helps to increase the readily available energy to the body to perform. Although this is great when needed, we shouldn’t need this hormone at high levels before bedtime as it could impair the quality of sleep, which may further impact our physical resilience and balance in our HRV.

Continuing with the theme of cortisol and its impact on sleep, three other lifestyle choices that result in the same are caffeine intake, alcohol consumption and smoking tobacco. So, any intake of these three compounds before bedtime will likely impair sleep quality.

In the case of caffeine, as it has a half shelf-life (in the bloodstream) of six hours, it means any caffeine intake after 12 o’clock midday is likely to prevent someone reaching the deep stage of sleep that is responsible for the majority of the restoration that comes with prolonged sleep.

One thing in particular that happens if we do not achieve deep sleep is we are more likely to have a higher activity in a brain area called the amygdala, which is linked with our fear response. A more active amygdala means we are more likely to be reactive, maybe irritable and less able to emotionally regulate. Poor sleep quality results in higher amygdala activity versus good quality of sleep, which helps to lower amygdala activity and therefore improve emotional regulation.

Photograph: iStock/rido franz

Outside of being physically active or making choices to improve sleep quality, another lifestyle choice we can make to improve our resilience is to train our brains. Practices such as mindfulness (not the same as meditation) can improve our ability to recognise and manage our emotions. Being more mindful is associated with stronger relationships, success and happiness at work and in our personal lives. In fact, in one study, eight weeks of mindfulness training significantly increased density in brain areas involved in learning, memory processes and emotion regulation.

Final considerations

Although we can manage our HRV balance with lifestyle, we must also accept that the causes of stress at home or in the workplace might have nothing to do with our lifestyle choices at all.

According to the Health and Safety Executive, there are six key areas that are most associated with causing stress in the workplace:

• Unreasonable demands being placed on employees
• Employees having no control over the way in which they do their work
• Lack of support from colleagues or managers
• Difficulties with relationships at work
• Ill-defined or unclear role
• Changes within the organisation not being managed well.

The law (in the UK) requires employers to tackle hazards including work-related stress and employers have a legal duty to firstly assess the risk of stress-related ill health arising from work activities and secondly take measures to control that risk.

So, alongside understanding what lifestyle factors may influence someone’s resilience, organisations should be completing suitable and sufficient risk assessments for work-related stress and taking action to tackle any problems identified by that risk assessment.

Marcus Herbert is head of wellbeing at British Safety Council.

For more information on supporting employee wellbeing see:

beingwelltogether.org

E: [email protected]