You don’t need a scientist to tell you that summer is associated with brightness, sunny beaches, uplifted spirits and the 5-year-old inside of you urging you to go outside. What you may not know, however, is that there is biological research explaining why people tend to be happier in the summer.
Let’s start off with some basic biology: melatonin is the hormone in our body that controls our sleep. Basically, when it’s dark outside, our bodies produce more melatonin which makes us feel sleepy. When it’s light out, our eyes sense the light and send a message to our brain to produce less melatonin, making us feel awake and alert during the day. It’s important to note that melatonin does not automatically make us feel sleepier but works to put our bodies in a groggier, more tired state of mind.
Now that we’ve taken a trip back to Grade 12 Biology class, let’s get back to summertime happiness. During summer months there is more light outside which makes our bodies produce less melatonin for shorter periods of time. This means our bodies are told to feel less sleepy and thus we feel less lazy and low-spirited in the summer.
For most of us, this seasonal phenomenon does not mean we suffer tragic changes in our lives in the winter months. Some people, however, claim to suffer from what’s called Seasonal Affective Disorder which, quite amusingly, goes by the acronym “S.A.D.” SAD is basically seasonal depression and people suffering from it report feeling clinical levels of depression only during winter months. It is found that 4-6% of North Americans report experiencing SAD and state that their depressive feelings disappear (or are significantly reduced) in summer months. It is also found that the overall rate of depression is much higher in winter months compared to summer. To support our earlier research, people suffering from SAD are found to be much more sensitive to light than the general public. This research shows that, unlike what people commonly assume, it’s the light not temperature associated with seasonal changes that affect our mood. It’s also important to note that daylight savings requires us to have shorter, darker days in the winter time which affects our light exposure in the winter.
Whether you feel “SAD” or just regular “sad” in the winter months, you now have an excuse to leave work early in the summer, so grab your flip-flips, get outside and soak up the sunlight!—for your health, of course.