As summer approaches, you may find yourself forgetting things, struggling to concentrate, or generally feeling cognitively slower. You may wonder, \u201cIs this normal? Does this happen to everyone?\u201d<\/p>\n
In past summers, this has certainly happened to me. For instance, I\u2019ve struggled with more tip-of-the-tongue words than usual. The ever-elusive names\u2014but also common words. Words like\u2026what do you call that thing you put on the dog? Not a collar\u2014the one with four straps?<\/p>\n
(Two minutes later): Harness.<\/p>\n
Is there something about the summer months that causes worse brain fog<\/a> and a sluggish memory?<\/p>\n Research shows the answer is yes. In fact, scientists have identified four key factors. And, fortunately, if you\u2019re aware of these harmful conditions, you can mitigate their effects.<\/p>\n Feature #1. Longer Days\u2014And Shorter Nights<\/p>\n Our brains require<\/a> a steady diet<\/a> of quality sleep to perform optimally.<\/p>\n But some research has shown that sleep suffers in the summertime. A study done in the Netherlands<\/a> revealed that sleep duration\u2014measured objectively with wrist-worn activity monitors\u2014was shorter in summer than winter.<\/p>\n In another study<\/a>, researchers in Germany examined brain activity during sleep across 12 months of the year. Although they found that overall time asleep did not change across seasons, REM<\/a> sleep did. In this study, REM sleep was reduced in spring and early summer and increased during the winter months.<\/p>\n And the REM periods of sleep are known to be important for some memory and thinking skills, such as consolidating emotional memories<\/a> in long-term memory<\/a>.<\/p>\n What\u2019s causing poor sleep in the summer? A major determinant seems to be extended daylight.<\/p>\n For example, a study<\/a> conducted in the Arctic summer\u2014with some periods of 24-hour sunlight\u2014showed that extremely long daylight was associated with disrupted circadian rhythms<\/a>, delays in melatonin secretion onset, and worse sleep.<\/p>\n Feature #2. Hotter Temperatures<\/p>\n Here\u2019s a sentence I never envisioned writing: Maybe Mel Torm\u00e9 was right: It\u2019s just tooooo darn hot.<\/p>\n Do sweltering temperatures also diminish our thinking abilities?<\/p>\n A group of scientists in the UK<\/a> investigated this. They brought volunteers into the lab to measure their mental agility in two thermal conditions: room temperature (70 \u00b0F) and an oppressively hot environment (103 \u00b0F).<\/p>\n In the heat, participants showed worse performance on a computer task that required inhibitory control\u2014the ability to ignore distractions and stay focused. That\u2019s an ability we often take for granted\u2014yet we rely on it constantly in daily life.<\/p>\n More broadly, studies<\/a> show that high temperatures impair both simple and complex cognitive tasks. However, it\u2019s much worse when doing something more demanding\u2014activities like doing mental arithmetic, planning how to solve a problem, and driving.<\/p>\n Feature #3. Dehydration<\/p>\n Another factor in summer\u2019s assault on thinking is dehydration. Summer brings two key risks: the aforementioned hotter temperatures and greater physical activity<\/a>.<\/p>\n Abundant evidence shows that dehydration impairs cognition<\/a>. And importantly, the drop in performance is more extreme in high-level cognitive tasks, such as those measuring attention<\/a> or logical reasoning, compared to low-level tasks, such as a simple reaction time measure.<\/p>\n The good news is that rehydrating with water reverses dehydration-associated dips in cognitive function<\/a>, including performance on memory and cognitive flexibility tasks.<\/p>\n Feature #4. Wildfire Smoke<\/p>\n I live in the Pacific Northwest. Here, as in many places, our summers are getting increasingly smoky from wildfires.<\/p>\n I personally seem to have more headaches on really smoky days, and I wondered if these pollutants were affecting my brain and thinking.<\/p>\n Unfortunately, they probably are. A recent review<\/a> showed that our brains are impacted by extreme heat, wildfire smoke, and the combination of the two. Specifically, these conditions are associated with inflammation in the brain and disruptions in neuronal signaling (the basis of all thinking).<\/p>\n Environment Essential Reads<\/p>\n For example, Cleland and colleagues<\/a> documented a link between smoke levels and reduced focused attention. They followed a large group of people for a year, tracking their scores on a test of selective attention and smoke levels. The two measures matched up. As concentrations of wildfire smoke and particulates went up, focused attention scores went down.<\/p>\n Maybe we\u2019d better step up those Smokey Bear ads again.<\/p>\n What You Can Do<\/p>\n Of course, your specific countermeasures to summer\u2019s harmful effects on thinking will depend on where you live and your lifestyle variables (to some degree\u2014no pun intended). But here is a buffet of advice to choose from.<\/p>\n Protect your sleep. Even if you live near the Arctic Circle, you can use blackout curtains or eye masks to create fake dark nights. Copyright Suzanna Penningroth<\/p>\n
\nStay cool. Use A\/C or fans, limit outdoor time, and avoid physical activity during the blazing hot hours (isn\u2019t it great to hear advice to exercise less?)
\nStay hydrated. Your goal should be light-to-clear colored urine. That\u2019s not a very scientific-sounding test, but it works without having to factor in multiple variables.
\nMinimize smoke exposure. Tips for this include using A\/C and avoiding outdoor physical activity when air quality is poor. See CDC safety guidelines<\/a> on wildfire smoke.
\nAnd, as a scientist, I can\u2019t help but mention one piece of advice for a broader, long-term solution for you and your fellow Earth inhabitants: Act to reduce global warming<\/a> (a main source of hotter temperatures and increased wildfires<\/a>). Remember that every little bit you can do helps.<\/p>\n