Wound Healing—Wound healing is of particular importance to the health of military members. Research is suggestive but not definitive of the relationship between sleep and wound healing. One intriguing study looked at the healing of blisters induced via suction in well-rested and sleep-deprived individuals. The results showed a difference, with the sleep-deprived individuals taking approximately 1 day longer to heal.13 This has some specific relevance to the military, as friction blisters can be common.30 A cross-sectional survey looking at a group of service members deployed in Iraq showed a prevalence of foot friction blisters of 33%, with 11% of individuals requiring medical care.31 Although this is an interesting example, it is not necessarily applicable to full-thickness wounds. A study utilizing rat models did not identify any differences between sleep-deprived and well-rested models in the healing of punch biopsy sites.32
Skin Cancer—Altered circadian rhythms resulting in changes in melatonin levels, changes in circadian rhythm–related gene pathways, and immunologic changes have been proposed as possible contributing mechanisms for the observed increased risk for skin cancers in military and civilian pilots.33,34 One study showed that UV-related erythema resolved quicker in well-rested individuals compared with those with short sleep duration, which could represent more efficient DNA repair given the relationship between UV-associated erythema and DNA damage and repair.35 Another study looking at circadian changes in the repair of UV-related DNA damage showed that mice exposed to UV radiation in the early morning had higher rates of squamous cell carcinoma than those exposed in the afternoon.36 However, a large cohort study using data from the Nurses’ Health Study II did not support a positive connection between short sleep duration and skin cancer; rather, it showed that a short sleep duration was associated with a decreased risk for melanoma and basal cell carcinoma, with no effect noted for squamous cell carcinoma.37 This does not support a positive association between short sleep duration and skin cancer and in some cases actually suggests a negative association.
Final Thoughts
Although more research is needed, there is evidence that sleep deprivation can negatively affect the skin. Randomized controlled trials looking at groups of individuals with specific dermatologic conditions with a very short sleep duration group (<6 hours of sleep per night), short sleep duration group (<7 hours of sleep per night), and a well-rested group (>7 hours of sleep per night) could be very helpful in this endeavor. Possible mechanisms include the HPA axis, immune system, and skin barrier function that are associated with sleep deprivation. Specific dermatologic conditions that may be affected by sleep deprivation include AD, psoriasis, alopecia areata, physical appearance, wound healing, and skin cancer. The impact of sleep deprivation on dermatologic conditions is particularly relevant to the military, as service members are at an increased risk for short sleep duration. It is possible that improving sleep may lead to better disease control for many dermatologic conditions.