Are Longer, Warmer Days Affecting Your Sleep?

The summer months bring longer, warmer days. We spend more time outdoors socializing, enjoying the warmth of the extended day. Vacations and day-trips are planned, gardens are given a spruce up in anticipation. However, a result of these longer days, which we may not consider, is the impact it can have on our sleep. 

Studies show that the different seasons can impact on the quality and efficiency of our sleep. This is an important consideration for all of us, and particularly for those with a disorder like sleep apnea.

The most common form of this disorder is obstructive sleep apnea, which causes frequent interruptions to sleep due to breathing difficulties resulting from blocked airways. The change in seasons has the potential to cause additional disruption to sleeping patterns.

How Longer Summer Days Can Affect Your Sleep

Most of us look forward to the longer, balmier summer days. However, the extra hours of sunlight can impact on our sleep/wake cycles. When sunlight starts to fade and darkness begins to set in our body produces the hormone melatonin. This hormone is produced by the pineal gland and is often called the hormone of darkness.

Melatonin production is an indicator to our bodies that it is time to sleep. When we are basking in some late, summer warmth, this exposure to longer hours of light can affect the production of melatonin. Longer hours due to the change of seasons can delay production of the hormone, impacting the signals for the body to sleep and our sleep/wake cycle. 

Depending on where you live, the length of the day and therefore the impact on melatonin production can differ too. For example, Seattle on the west coast may receive 16 hours of sunlight in a day, while on the east coast, Miami may receive only 14 hours of sunlight.

Is Everyone Impacted in the Same Way by the Seasons?

As we get older, our sleeping patterns can alter quite significantly. Therefore, it should be no surprise that studies show the older you are the more likely the seasons will impact on your sleep/wake cycle. What may be a surprise is just how much this impact can be.

Those over 60 years of age were shown to receive 40 minutes less sleep on the day of the summer solstice than the under 30’s. The accumulation of this lack of sleep over the longer days of summer could be significant. As the risk of obstructive sleep apnea can increase with age, then age-related seasonal differences in sleeping quality is worth noting.

However, this does not mean that younger adults can ignore the impact of seasonal influences.

The Evidence of the Influence of Longer, Warmer Days

During the longer, warmer days, analysis shows there is a shift in sleeping patterns. Americans went to bed 10 minutes later each night and woke up 10 minutes later each day compared to later months in the year. The longer the day, there was less sleep that night, signaling a shift in the sleep/wake cycle brought about by the change in season.

Analysis also indicates that the average American receives 10 minutes less sleep each day during the month of June. It may not sound much, but if this pattern continues across the whole month that adds up to a loss of 300 minutes, five hours, of important recuperative rest.

Around the time of the summer solstice the analysis shows Americans receive just under 6 hours of sleep a night, compared to 6 hours and 12 minutes between November and December. This reduction in time spent in bed was further magnified at the weekend, with the average American losing 20 minutes of sleep in the summer compared to the darker, cooler months of winter. This can be looked at against the fact that adults are recommended to get 7 to 8 hours of sleep each night. 

Yet it is not just time asleep that matters, but sleep efficiency too. Sleep efficiency relates to the total sleep time against the total time spent in bed. Again, here there is a drop off for Americans in the summer months. 

The National Sleep Foundation advises we aim for a sleep efficiency threshold of 85%. However, even in November, Americans post a sleep efficiency threshold of only 80%. By July this has dropped further to 77%.

A Holiday Trend Reversal

An interesting reversal is seen in the holiday season at the end of the year. Most of us look forward to the holiday season as we do the longer summer days. However, the end of year holiday period comes with less daylight hours and cooler temperatures.

Just as we start going to bed later -- and also rising later in the summer -- the same pattern emerges during the end-of-year holiday season. In December the average bed time is 8 minutes later than in November, with people awaking 10 minutes later the next morning on average too. 

Therefore, as in Summer, there is a shift in the sleep/wake cycle for a particular time of the year. The difference to summer is there is no accompanying decline in sleep times. In fact, this time of year is when Americans average most sleep, around 6 hours and 15 minutes each day. Sleep efficiency was also up at nearly 80%.

Tips For Year-Round Better Sleep

There are a few ways to help improve your sleep throughout the year which are backed up by science.

  • Ensure the bedroom is a place for sleep, not a place to work or watch TV. This helps train the brain to associate the bedroom with sleep.
  • Limit blue-light emitting screen time in the evening to ensure the body releases the hormone melatonin at the right time.
  • Avoid eating large meals and spicy foods later in the evening to allow your body to concentrate on sleep and not digestion when you go to bed.
  • Cut out caffeine in all its forms after 2pm each day, as caffeine is a stimulant whose affects can have an impact for hours.