How can we scientifically measure stress
No direct measurement of stress
There is no way to measure stress directly, but we can get an indication of the levels of stress in the body by measuring some of the physical affects in the body which are affected by stress. So for example we can measure the
- Heart rate
- Blood pressure
- Breathing rate
- Brain waves
- Muscle tension
- Skin resistance
- Temperature
There are various meters and machines which can be used to measure the above. This section looks at how these machines can be used to measure stress. There is also a short section on biofeedback.
Biofeedback uses these machines to indicate to the person the level of stress, which they are experiencing. They then use this ??feedback?? to reduce the levels of stress they are experiencing.
All of the above bodily functions are affected by things other than stress, so it is important to realize that to get a good true indication of the level of stress that a person is experiencing, one needs to take several of the reading above to give a more accurate level of the amount of stress the person is experiencing.
Heart Rate
Heart rate can be measured by using an EEG or a heart rate monitor. The modern machines give a digital readout out of the current heart rate. It is constantly being monitored and shows an increase or decrease in the heart beat rate as it happens.
This is easy to measure. However, heart rate is affected by many factors other than stress.
Blood pressure
Blood pressure can be measured by a blood pressure gauge, which usually is taken by applying a pressure pad to ones arm attached to a meter, which gives a reading of both the systolic and diasystolic blood pressure. However, some smaller meters are available which can give a good reading of blood pressure by calculating the milliseconds between when the heart beats and when the pulse of blood reaches the wrist.
Blood pressure is affected by stress and tends to get higher as the person becomes stressed. However, there are many things, which can also higher the blood pressure, and also many factors, which can lower it.
Breathing rate
Breathing rate may be measured by an EEG or by simply timing how long it takes a person to take 10 breaths.
Again this rate is usually highered by stress, but is also affected by many things other than stress.
Brain Waves
Brain waves give an indication of the level of activity of the brain. The frequency of electrical activity of the brain is measured by placing electrodes on the head and measuring the tiny electrical potential picked up by these electrodes. When the person is wide awake doing normal activities this is known as Beta waves. When the person becomes very relaxed the Alpha waves are produced which signify less activity or disturbance of the brain waves. Delta waves are usually released when we sleep but can also be sometimes noticed during deep meditation.
Brain waves are measured by an ECG. Again however, although the presence of Alpha waves generally does indicate a very relaxed state, the presence of Beta waves does not necessarily indicate high levels of stress.
Muscle tension
Muscle tension is measured by an EMG. This measures the electrical potential close to certain muscle groups. In general large amounts of minute muscle activity indicate tension in that area, which is also a good indicator of levels of stress.
Each of us tends to hold tension in different muscles depending on our makeup. However, tension is often held in the neck, shoulder and upper back area. For this reason, the muscle tension in this area can be a good indicator of levels of stress the person is experiencing.
EMG are reportably difficult machines to use accurately and are also quite expensive.
Skin resistance
Skin resistance is affected by the amount of sweat on the skin which in turn is affected by the opening or closing of the pores. This affect of the body occurs at the unconscious level and while sitting down and inactive, is quite a good indicator of the levels of stress a person is experiencing.
2 electrodes are placed a small distance apart on the skin (usually on the fingers). The electrical resistance is measured between these two electrodes, and as the resistance decreases this indicates that the person is sweating slightly more and is becoming more stressed.
This machine is commonly know as a lie detector, but the scientific name is a galvanometer.
Temperature
As was indicated by the section on changes in the body produced as a result of stress, blood flow is diverted away from certain areas and towards others. The forehead is one area where the blood is directed away from as one becomes stressed, and thus the temperature of the skin on the forehead drops as one becomes stressed. This can be measured easily using a thermometer.
Again, the temperature of the forehead can be affected by things other than by stress.
Bio-feedback
Biofeedback is a term used to address a situation where a person uses a mechanical meter to indicate some response in their body, in order to improve their awareness and control of their body response.
Many responses in our body are unconscious and we are neither aware of the activation nor sometimes of their levels of functioning. One example is the opening/closing of the pores in our body.
A typical biofeedback setup would be a skin resistance machine which has an audible sound linked up to the level of resistance detected. So the more stressed a person becomes, the higher the pitch of the sound. When the person is ??hooked up?? to this machine for a while, their body begins to learn what/how affects the pitch of the sound, and they begin to learn how to reduce and let go of any tension.
The uses of biofeedback are very varied and range from stress relief to toning of muscles as in pelvic floor training for incontinence.
Managing stress
A good way of learning stress management is to attend a yoga course which is specially suitable for stress reduction.
Satyananda Yoga
