Monday blues?

Social jetlag - getting to bed and waking up more than an hour later than usual over the weekend will give you that groggy feeling on a Monday. Just three hours delay on Friday and Saturday can increase blood pressure - Acute social jetlag augments morning blood pressure surge: a randomized crossover trial, and regular social lag (just one hour or more variation) can increase your risk of chronic kidney disease - Association between social jetlag and chronic kidney disease among the Korean working population, and increase your risk of feeling stressed at work - Association of sleep duration on workdays or free days and social jetlag with job stress.

As the mornings get darker and colder up here in the North, it’s even harder to rise and shine.

You can’t undo your weekend - but you can take control of your Monday morning by giving your body clock a blast of bright light first thing. 

If your commute is all underground, it’s still dark when you arrive and you can’t sit near a window, artificial lighting can help.

One study found dynamic lighting that delivered higher melanopic lux in the morning (931± 484 melanopic lux in the test v   730 ± 390 melanopic lux in the control) brought the timing of melatonin onset (one of the markers of circadian entrainment) earlier that evening - Optimized office lighting advances melatonin phase and peripheral heat loss prior bedtime. There are a number of studies including these that suggest that lighting that changes over the course of the day can improve visual comfort and engagement and even brain activity in day-active office workers - An experiment of double dynamic lighting in an office responding to sky and daylight: Perceived effects on comfort, atmosphere and work engagement, The effect of dynamic correlated colour temperature changes on alertness and performance, Contrasting dynamic light scenarios in an operational office: Effects on visual experience, alertness, cognitive performance, and sleep, Diurnal effects of dynamic lighting on alertness, cognition, and mood of mentally fatigued individuals in a daylight deprived environment, but the ‘perfect light recipe’ for circadian entrainment is still in debate.

If you’re still struggling to stay awake, a power nap might just help. This fascinating review of the nap paradox explains that just ten minutes is optimal to boost memory, focus and even help you manage your mood. Equally, chronic daily napping is associated with a range of poorer health outcomes including cognitive decline, hypertension, diabetes, with a potential link with inflammation - Exploring the nap paradox: are mid-day sleep bouts a friend or foe?

Morning light is only half the picture though.

You need to make sure you let your brain know it’s time to switch off. This study found half of homes had bright enough light to suppress melatonin by 50%, although there are wide range of individual responses (0–87% suppression for the average home), children are more sensitive than us older folk - Evening home lighting adversely impacts the circadian system and sleep.

Even when you’ve turned off the lights indoors, light pollution from the street can still stop you getting your beauty sleep, contributing to mental and physical health problems - Sleep problems mediate the association between outdoor nighttime light and symptoms of depression and anxiety: A cross-sectional, multi-city study in Bulgaria. American adolescents living in areas with the highest light pollution were at 16% higher risk of anxiety disorder, even after adjusting for socio-economic and other factors - Daily rhythms, light exposure and social jetlag correlate with demographic characteristics and health in a nationally representative survey.

Making sure it’s dark with black-out curtains, switching off standby lights or using an eye mask will help us all to feel brighter tomorrow.