By Michael Carrera, MSc.
and Natasha Vani, MSc., ATCP

It is estimated that over 340 million people in the world suffer from depression. Half of all victims do not recognize the illness and therefore never seek help. Untreated, depression is the most common cause of suicide and the incidence is unfortunately, on the rise. The World Health Organization has estimated that by the year 2020 “depression will be the greatest burden of ill-health to people in the developing world, and severe depression will be the second largest cause of death and disability”.

With these overwhelming statistics in mind, several questions arise. For starters what exactly is depression? We all have changes in mood from day to day, and we all have episodes in our life when we are sad for prolonged periods of time. Whether due to bereavement, unemployment, or even social isolation, when does too much sadness change from a natural occurrence to a serious disorder requiring help? And what are the causes of depression? Can we do anything to prevent them?

What is Depression?
Depression is a pervasive illness affecting almost 3 million Canadians. Depression is considered a mood disorder which is complicated by multiple and somewhat unclear causes. The symptoms may vary between individuals as do successful treatments.

What differentiates someone who is sad from someone who is considered clinically depressed? Since the term is over simplified and often misused, the true diagnosis should be left to the medical profession. However, psychologists will generally search for symptoms involving feelings or signs such as the following: 

• Depressed mood most of the day
• Fatigue or loss of energy
• Feelings of worthlessness
• Decreased ability to think or concentrate
• Loss of pleasure in all or most activities
• Weight loss or weight gain without conscious efforts

Causes of Depression?
Depression has been shown to run in families suggesting a possible genetic connection. It is more common in women, and may become more visible in those with certain personality traits such as pessimism. Environment, lifestyle and stressful events may also play a role in depression as well as certain brain chemicals. It is actually the brain chemicals which have sparked the interest of many researchers including those involved in exercise studies.

To date, researchers have been searching for a link between exercise and a possible cause/treatment of depression through the study of various neurotransmitters in the brain. Two of interest and which relate to exercise are Serotonin and Norepinephrine. Some research currently demonstrates that these two chemicals are lower in depressed patients and exercise is believed to be an effective method of naturally increasing them, therefore current studies are attempting to determine if a true link exists involving exercise as a potential natural treatment in depressed patients.

The primary function of serotonin is regulation of our emotions and it has been suggested that low levels may cause large mood swings and more impulsive behavior. Norepinephrine on the other hand helps us interpret and act on emotions and combined with other regions of the brain, controls physical desires such as sleep, appetite and reaction to stress. According to the American Medical Association, heavy exercise may increase serotonin levels and these levels may last up to one hour after the workout.

It has also been suggested that prolonged exercise increases brain serotonergic activity. With respect to norepinephrine, it is a fact that this chemical is released with exercise, and data exists suggesting that both acute and chronic exercise bouts may play a role in the regulation of the deficient chemicals.

While there is a clear possibility that a link exists between serotonin, norepinephrine, depression and exercise, further research is needed.

Can exercise increase mood and help with those mildly depressed? The answer to this is clearly yes.

Whether you follow an exercise program or simply take part in some form of random activity, exercise without a doubt, increases your energy levels and improves your attitude and your ability to focus. Exercise may promote social behavior, acceptance and fight boredom, and of course helps regulate weight and body image—improving appearance, self confidence and creating an overall feeling of well-being.

References