Physiology at Firstbeat
Stress can be positive!
Stress is defined as the body’s physical and mental responses and adaptations to real or perceived changes and challenges in life. While the creation of stress reaction can be attributed to a variety of common internal and external factors, perception of stress can vary significantly between individuals. Internal stress factors include lack of sleep, use of alcohol and poor nutrition. External stress factors include for example work-related stress related to work, financial issues, and social relationships. Stress management training and learning to cope with stress-related thoughts and feelings can have a tremendous effect in reducing internal stress levels.
Stress becomes visible through increased activation levels of the body. Activation levels are governed by the autonomic nervous system (ANS) which regulates gastrointestinal, endocrine, cardiovascular and pulmonary systems to facilitate the demands of daily life.
The two divisions of the ANS are the sympathetic and parasympathetic divisions
- Parasympathetic Division Activity: Restores and maintains the body’s resting condition
- Sympathetic Division Activity: Prepares the body to meet challenges
Sympathetic nervous activity accelerates bodily functions (i.e., physiological stress reaction). The stress response results in increased activation of stress-hormone secretions (cortisol, catecholamines), increased blood pressure and HR and decreased HRV. This has important implications for stress research. ANS function can be assessed noninvasively using HR and HRV.
It is important to note that stress is not always harmful. Stress can be positive or negative. The presence of stress may indicate that the person is experiencing something exciting or joyful. However high stress indicators over a long period of time negatively impact personal well-being and health. Moderate stress levels during a normal working day are associated with high productivity at work.
Recovery balances daily stress
Regular recovery is necessary for physiological systems to overcome the effects of stress. Recovery means reduced activation levels in the body in the absence of internal and external stress factors. During recovery, parasympathetic (vagal) activations dominate the ANS and psychophysiological resources are restored.
The connection between HRV and stress-recovery is commonly recognized. Strong indicators of recovery include individually low HR and high HRV. Night-time recovery rates are a key factor in stress management. Getting enough sleep and sleep quality are especially important during demanding periods of life. In general, adults need about 6-8 hours of high-quality sleep each night. Adequate physical activity and proper nutrition are components of a healthy lifestyle that induces good recovery during sleep. Falling asleep may be difficult after a hectic day, or sleep may be disturbed by waking up too early. Good time management allows a person to finish daily work earlier, allowing activities and relaxation before going to bed. Strenuous exercise and drinking alcohol should be avoided late in the evening since they may delay falling asleep and inhibit the recovery process.