<P> A 2017 study in the American Economic Journal: Applied Economics estimated that "the transition into DST caused over 30 deaths at a social cost of $275 million annually," primarily by increasing sleep deprivation . </P> <P> DST has mixed effects on health . In societies with fixed work schedules it provides more afternoon sunlight for outdoor exercise . It alters sunlight exposure; whether this is beneficial depends on one's location and daily schedule, as sunlight triggers vitamin D synthesis in the skin, but overexposure can lead to skin cancer . DST may help in depression by causing individuals to rise earlier, but some argue the reverse . The Retinitis Pigmentosa Foundation Fighting Blindness, chaired by blind sports magnate Gordon Gund, successfully lobbied in 1985 and 2005 for U.S. DST extensions . DST shifts are associated with higher rates of ischemic stroke in the first two days after the shift, though not in the week thereafter . </P> <P> Clock shifts were found to increase the risk of heart attack by 10 percent, and to disrupt sleep and reduce its efficiency . Effects on seasonal adaptation of the circadian rhythm can be severe and last for weeks . A 2008 study found that although male suicide rates rise in the weeks after the spring transition, the relationship weakened greatly after adjusting for season . A 2008 Swedish study found that heart attacks were significantly more common the first three weekdays after the spring transition, and significantly less common the first weekday after the autumn transition . A 2013 review found little evidence that people slept more on the night after the fall DST shift, even though it is often described as allowing people to sleep for an hour longer than normal . The same review stated that the lost hour of sleep resulting from the spring shift appears to result in sleep loss for at least a week afterward . In 2015, two psychologists recommended that DST be abolished, citing its disruptive effects on sleep as one reason for this recommendation . </P> <P> The government of Kazakhstan cited health complications due to clock shifts as a reason for abolishing DST in 2005 . In March 2011, Dmitri Medvedev, president of Russia, claimed that "stress of changing clocks" was the motivation for Russia to stay in DST all year long . Officials at the time talked about an annual increase in suicides . </P>

When did daylight saving time begin and why