The World Health Organization (WHO) describes stress as the most dangerous threat to health in the 21st century. Reason enough to take a look at this topic from a medical perspective.
Especially in the current times, mental health plays a special role. It is important to recognize stressors and learn strategies to deal with them. We show how stress affects our body and how we can measure it to determine acute and chronic stress.
Definition of stress
A universally valid definition of stress is hardly possible, as each person experiences different situations and circumstances as stressful. These can be burdens and challenges of a physical, emotional or psychological nature that one feels unable to cope with, as well as noise, a hectic pace or a perceived threat of losing control. It is precisely this individual perception that plays a decisive role in the topic of stress. Around one in three Germans today talks about feeling permanently stressed in their subjective context.
If we look at evolution, stress has a protective function, as automatic processes are activated in the event of danger and threat, which could save our lives if necessary. Many thousands of years ago, if a dangerous animal stood in front of us, the body had to be on the alert at lightning speed and be able to react: Flight or fight? In any case, this required top performance. Nowadays no tigers or mammoths stand before us and the stressors have changed, however the stress reaction of our body remains the same.
In the stress model of Lazarus a primary evaluation of the situation takes place by the exact interpretation of the stressors. If this should turn out “dangerous”, the secondary evaluation follows by means of the analysis of available resources. Should these be insufficient, we feel stress. If they are available in sufficient measure for coping, we remain calm. In the process, existing coping strategies are also assessed and the stressful situation is constantly re-evaluated. Thus, in addition to objective circumstances, subjective coping in particular plays a decisive role. Stress is therefore a subjective perception and evaluation.
When we come into contact with stressors, we feel stress, which can be additionally intensified by our own impatience or perfectionism, for example. It is very important to remember that both external and internal stressors, such as negative thoughts and evaluations, contribute to the perception of stress. The personal attitude of the person has a significant impact, because it allows both to increase and decrease stress.
Furthermore, a distinction is made between eustress and distress, whereby eustress can have a good and beneficial effect and distress, as the stress typical in the vernacular, has rather negative effects and can even cause illnesses – especially if it is present in the long term.
Effects of stress on the body
Our body reacts to external and internal stress with the stress response, which affects different levels: physical, emotional, mental and behavioral.
During stress, the sympathetic nervous system of our autonomic nervous system is activated and stress hormones are released. The so-called stress metabolism comprises over 20 reactions in the body. For an “instant effect,” adrenaline is released at lightning speed, causing central vessels to dilate, blood pressure to rise, and heart rate to accelerate. Our bronchial tubes are also dilated to allow for improved gas exchange. Overall, this makes more energy available to our bodies in the face of acute threat and danger.
Especially during prolonged stress, endogenous cortisol is also released into our blood. Cortisol increases blood sugar and fat levels in the blood so that more energy is available for fight or flight. To do this, the body taps into sugar stores in the liver and even sacrifices muscle. This is broken down, while visceral fat increases when combined with an unfavorable diet. The hormone cortisol thus initially serves to improve stress management until the organism reaches exhaustion and secondary diseases can develop. The risk of diabetes, metabolic syndrome, tumors and cardiovascular diseases such as heart attack, stroke and arteriosclerosis increases.
The list of stress-related physical consequences is long. In the short term, for example, the heart and respiratory rates and muscle tone increase as part of the stress reaction. In the long term, stressed people often suffer from fatigue, headaches, lack of energy and performance, poor concentration, nervousness, sleep disorders, or an increased susceptibility to infections and inflammations.
The thinking capacity of the cerebrum is reduced so that reflexes (to ensure survival) can run, but nowadays it is mainly cognitive performance that suffers. Long-lasting, increased muscle tone can cause tension or chronic pain conditions. In addition to hormone-induced weight gain, the feeling of hunger is also suppressed until craving attacks occur in the evening and the calories then consumed are stored much more quickly. In addition, various hormones become imbalanced, sexual desire decreases and cells age faster.
Psychologically and scientifically validated questionnaires can be used as the simplest option for measuring stress levels. These specifically ask about psychological stress, stress factors and triggers, resulting distress, symptoms, reactions and coping strategies. Some scores also attempt to derive recommendations for action, while others are used to examine specific types of stress, such as burnout, in greater detail.
Stress causes objectively measurable body reaction patterns, especially through the release of hormones, which can be used for (indirect) stress diagnostics. Skin resistance can be assessed via electrodes on fingers and palms. The electrical conductivity of the skin is measured. In the case of poor conductivity, the skin resistance is high; in the case of stress, on the other hand, the associated sweating increases the conductivity and thus reduces the skin resistance. This method is used, for example, in lie detectors or biofeedback training. In addition, the increased cortisol level in saliva, blood or urine, especially during chronic stress, can be measured.
A non-invasive and widely used variant for stress measurement is heart rate variability (HRV) measurement. The measurement is based on a performed ECG in which the heart rate is measured. Even if the heart rate is stable, the distance between the individual heart contractions or the associated electrical excitations in the ECG is not exactly constant and the time intervals between successive heartbeats change minimally. The difference or deviation in spacing is expressed in milliseconds and represents heart rate variability (HRV). The higher the standard deviation between each ECG beat, the higher the HRV. The higher the HRV, the better. In simple terms, a high HRV means that the body can adapt better and faster to external and internal influences and can therefore enter a parasympathetically triggered relaxation and rest mode more quickly. Due to this, a high HRV can be concluded to a currently low stress level and vice versa.
In this context, breathing also affects our heart rate: When we inhale, the heartbeat becomes a little bit faster and when we exhale, a little bit slower (so-called RSA = respiratory sinus arrhythmia). Therefore, slow, deep breathing acts like a trigger for relaxation, i.e. parasympathetic.
In HRV measurement, different protocols can be applied: one can derive HRV continuously over 24 hours or perform a 5-minute resting measurement while lying down and combine it with another breath measurement (so-called RSA measurement, to determine respiratory sinus arrhythmia). In the aforementioned breath measurement, the participant breathes under guidance at a very slow breathing rate of 6 breaths per minute, which affects HRV and provides further valuable information about a person’s stress state. If the rest measurement and breath measurement are equally low, the result indicates chronic stress. If the rest measurement shows a low HRV, but the breath measurement shows a higher HRV, this indicates acute stress.
If you know your own stress level and are aware of stressors in your environment, you can take specific measures to lower your stress level. In this way, you can both strengthen your mental health and minimize physical effects.