Type 1 diabetes (T1D) is a very disruptive condition. It interferes with work, school, mealtimes, romance, and everything in between. From carb-counting to insulin dosing, to beeping pumps and continuous glucose monitors (CGMs), to symptoms of high and low blood glucose, T1D causes countless interruptions throughout the day—and, unfortunately, the night.

Not surprisingly, nighttime disruptions have a profound impact on sleep. As one 2018 literature review by Perez et al. reported, people with T1D “experience higher rates of sleep disturbances than people without diabetes, and these disturbances have negative implications for glycemic control and diabetes management, as well as psychosocial and cognitive outcomes.”

Quality sleep is an important component of well-being, mental and physical, for everyone. For people with T1D, sleep is yet another factor that can affect blood glucose levels, insulin sensitivity, and long-term health outcomes.

How Does T1D Affect Sleep?

The relationship between T1D and sleep is a complex one, and it is made more complicated by a minimal body of research that relies heavily on self-reporting. Having lived and slept with T1D for years, I know my own sleep has often been impacted by hyperglycemia, hypoglycemia, and fear of hypoglycemia (FoH). These causes have been tentatively explored in the research on T1D and sleep, but some more than others.

Perhaps the least explored of these topics is the impact of hyperglycemia on sleep. One of the primary symptoms of hyperglycemia is frequent urination, also known as “osmotic diuresis.” Common sense would dictate that it is tough to get a restful sleep when you wake every hour to use the bathroom, and I can personally confirm that nocturnal hyperglycemia has this effect for me. However, as of 2016, no formal studies had been reported on this topic according to a comprehensive literature review by Farabi.

Studies on hypoglycemia and sleep—particularly the physiological impact on sleep stages—are also limited. However, subjective self-reported studies provide some insight. In one large 2011 study by Brod, Christensen, and Bushnell, 13.3% of respondents with T1D reported being unable to return to sleep after experiencing a mild nocturnal hypoglycemic event, and just 32.4% reported having a good night’s sleep compared to a normal night. The results of these surveys mirror my own feelings and experience with this phenomenon. Whether I am woken by my CGM alarm or by hypoglycemia symptoms, I often do find it difficult to return to sleep.

In addition to hypoglycemia itself, FoH sometimes affects my sleep quality, especially when my blood glucose levels are less consistent than usual. There has been some research that aligns with this experience, including a 2018 study by Martyn-Nemeth et al. which reported that patients with poor sleep quality also had “significantly greater nocturnal glucose variability and FoH.” This correlation makes sense: It is difficult to sleep when you can’t trust your own body.

FoH is also a significant challenge for children with T1D and their parents. One 2017 survey of T1D Exchange Registry participants reported that poorer sleep quality in children was associated with poorer parental sleep quality, parental well-being, and fear of hypoglycemia. Another similar T1D Exchange Registry survey concluded that “the greatest worries of parents of young children with T1D were related to hypoglycemia during sleep and other times/circumstances during which it would be difficult to detect hypoglycemia.”

How Does Sleep Affect T1D?

Regardless of the cause of sleep disturbance, poor sleep is strongly associated with increased glucose variability. In one meta-analysis of 22 studies, Reutrakul et al. found that adults with T1D who slept less than six hours had poorer glycemic control. The question is, does glucose variability cause poor sleep, or does poor sleep cause glucose variability?

Both are probably true. As discussed above, self-reported surveys generally reflect my own experiences of sleep disturbances caused by hyper- and hypoglycemia (i.e., glucose variability). There is also evidence to support the idea that sleep deprivation affects insulin sensitivity, and with it, glucose levels. One small 2010 study by Donga et al. found that a single night of partial sleep restriction reduces insulin sensitivity by 14–21%. In other words, a bad night’s sleep can actually significantly increase the amount of insulin a person needs the next day—though not, in my experience, in a predictable way.

These changing physical needs, combined with the mental effects of poor sleep, can make blood glucose management incredibly challenging. Like most people, living with diabetes or not, I am usually irritable after a night of poor sleep. On top of this, reduced insulin sensitivity makes it tougher to manage my blood glucose, which in turn makes me even more irritable. After a night or two of bad sleep, dealing with the regular maintenance of T1D can feel nearly impossible.

How Does Sleep Affect Mental Health?

Of course, sleep is an important component of mental health for everyone—not just people with diabetes. According to Harvard Health Publishing, “Neuroimaging and neurochemistry studies suggest that a good night’s sleep helps foster both mental and emotional resilience, while chronic sleep deprivation sets the stage for negative thinking and emotional vulnerability.”

Resilience and decision-making skills are particularly important when it comes to diabetes outcomes. When people living with T1D experience mental health challenges—whether due to sleep deprivation, mental illness, or other reasons—their ability to self-manage their condition also suffers. In this way, addressing sleep issues may be a concrete way to improve long-term health outcomes, both mental and physical, for people with T1D.

It might be a while before research catches up with the realities of sleeping well with T1D. As with everything else related to living with T1D, an individual approach to sleep challenges will always be best. For me, using a CGM has made a significant difference in my sleep quality. It helps me prevent nocturnal hypoglycemia, particularly severe episodes, and in doing so it has also reduced my FoH around sleep. Establishing other good sleep hygiene habits, like reducing screen-time before bed, can also be incredibly helpful.

Of course, even equipped with a CGM, mindful habits, and the best of intentions, I still experience T1D-related sleep disruptions sometimes. I don’t think that will ever change, though a girl can dream . . .