In Silicon Valley, it seems that the world never sleeps.
In this haven for all-hours start-ups and venture-capital firms with global connections, high-tech workers are joining doctors, nurses, paramedics and emergency vets; truck drivers; pilots, flight attendants and air-traffic controllers; janitors; retailers; and those with international business pursuits, who often work at night or on rotating timetables.
For locals who put in long hours with irregular schedules, getting enough high-quality shut-eye can be a challenge. Around 15 percent of fulltime workers in the U.S. are shift workers (defined as not only those on evening or rotating shifts but any nonstandard hours and schedules), according to a 2009 Current Neurology and Neuroscience Reports article.
Stanford School of Medicine professor and sleep researcher Dr. Jamie Zeitzer, an expert on circadian rhythms and sleep disorders, said one's slumber schedule -- or lack thereof -- can and does have a major impact on overall, long-term health.
"The biggest problem with sleep disorders is that effects are long-range. You might live a few years less long; the medical issues are less concrete for people so they don't take it as seriously. They'll say: 'It's just sleep. Suck it up,'" Zeitzer said. "Shift work interferes with the circadian system so that you're awake when you want to be asleep. Events that normally go together start fading apart. It eventually leads to higher rates of cancer, obesity and diabetes."
One of his current research studies focuses on the potential connections among circadian rhythms, sleep disruption and breast-cancer survival rates.
Sleep deprivation can also lead to problems in more acute ways.
"There have been lots of studies in the last 10 years showing that most major disasters that have occurred are associated with night shifts or sleep deprivation," said Zeitzer, naming the Exxon Valdez oil spill as an example. "Trying to live in a 24-hour society just doesn't work as well. There are more accidents, more car crashes and more errors. Every time you get in an airplane, you have no idea what your pilots' schedules are like."
Medical interns working extended shifts reported making more medical errors (including those that harm or kill patients), had a 60 percent increase in the odds of suffering an occupational injury, and have twice the odds of suffering motor-vehicle crashes on the drive home from work, a June 2011 article in the journal Science of Nature and Sleep states.
People really do need about eight hours of sleep (whether it be day or night) to function at optimum levels, Zeitzer said.
"Some aspects are psychological in nature. Feeling tired and being tired are two different things. People can feel alert, but if the hospital tests them they respond as if they were tired," he said. "You can't compensate. An extra cup of coffee just doesn't cut it."
Maintaining as much consistency as possible, as well as napping before starting on a shift, can help mitigate the impact, he said.
In July, the Accreditation Council for Graduate Medical Education enacted a rule that first-year residents may work no more than 16 hours without rest, as reported in the Nature and Science of Sleep article.
"Extensive scientific data demonstrate that shifts exceeding 12-16 hours without sleep are unsafe," the report states. "Schedules should be designed that adhere to principles of sleep and circadian science; this includes careful consideration of the effects of multiple consecutive night shifts, and provision of adequate time off after night work."
The Stanford Sleep Clinic's website suggests that adjusting light exposure (blackout curtains or eye shades), taking certain "alerting medications" and trying behavioral techniques may be helpful to sufferers of "Shift Work Sleep Disorder."
Sleep cycles are a crucial factor in a number of biological functions.
The body's internal 24-hour clock, the circadian system (named from the Latin "circa" and "diem," meaning "about a day"), "controls the timing of various systems in your body so that all the wake-related functions happen when you're awake and vice versa," Zeitzer explained.
"The central clock in the brain keeps time and coordinates with blood cells, skin cells, cells everywhere in the body, the idea being that it doesn't make sense to have your gut, your liver, processing food when you're asleep."
Circadian systems are present in all animals, from single-celled organisms to dogs to humans.
"Sunlight tells the internal clock what time it is," Zeitzer said. "Jet lag is basically the body adapting to new time zones, and the light and darkness will tell the internal clock what time you want to be on."
The body's use of light exposure as a natural alarm clock doesn't work so well for those who aren't on a standard daylight schedule.
"For shift workers, one issue is that exposure to light and dark is erratic," Zeitzer said. However, people can adjust to working nocturnal hours. It's switching back and forth between schedules that is especially problematic.
"Consistency is the most important aspect. You can turn someone into a night person but sometimes they work a night schedule during the week, then they revert to a standard system on the weekend (for family or social time). That's the root of the problem, so help is limited," Zeitzer said.
Adobe Animal Hospital veterinarian Layla Shaikh's current schedule at the Los Altos clinic includes three overnight shifts a week, plus one day shift.
"I work an 11- to 12-hour shift. It equals about 40 to 50 hours a week," she said.
When on the night shift, she comes in around 8 p.m., with another vet overlapping until 9 or 10 p.m. During the slowest part of the night (1 to 4 a.m.), there are usually two nurses and one doctor on duty.
Shaikh estimated treating an average of eight to 10 patients a night. After 10 p.m., the clinic is open for emergencies only, though what constitutes an emergency can vary.
"Last night someone found fleas on his cat at 1 a.m." and brought it in for treatment, she said. But she sees a wide range of cases, such as pets having trouble breathing, problems walking or gastrointestinal distress.
Shaikh, 30, has been working nights for five years. Switching between night and day shifts has "gotten a little harder for me now that I'm older. It's gotten tougher for me to make the shift," she said. She prefers to work nights for a week straight, then have a week off, then a week of day shifts, and so on -- a schedule she will switch to next month. She does worry about the impact of her schedule on her health.
"When I work nights I get headaches more frequently. I'm more susceptible to getting colds," she said. "Coming off nights and going to days is really tough," especially adjusting her sleeping habits on the days between her night and day shifts.
"I come home in the morning, hang out with my husband for a few minutes before he goes to work and go to sleep."
Spending only a few moments a day with her husband, who works long hours in the finance industry, is hard, she said. But at least, she added, "I don't have children. Children would really complicate things."
In order to cope with her irregular schedule, "the most important thing is making sure to communicate with the people who are important to my life that I really do need to sleep during the day. I turn off my phone and have to tell people that is really something I absolutely need to do," she said. "People don't always understand. They say, 'Well, you're home ...' Yeah, not really."
She finds it particularly difficult to go to sleep after daybreak.
"It's so rewarding getting home before the sun comes up. To be in bed before the sun is shining, it makes a world of difference."
But though it's taxing, her job is full of rewards, too, she said.
"You work fewer shifts, which is nice. And it's fun overnight. The nurses who work overnight are really intelligent, really hard workers and really fun."
Working with emergency patients, "You really, really help your clients in crisis situations; it's very rewarding. If you like emergency medicine, it's worth that sacrifice.
"Is it sustainable in the long term? Not for everybody."
Palo Alto resident Mel Kronick, the former CEO and current board member of Population Genetics Technologies, based in Cambridge, U.K., leaps into his work day near dawn while his British co-workers, eight hours ahead, are approaching the end of theirs. Kronick said he doesn't usually feel sleep deprived since he keeps a fairly regular schedule ("only once have I had to do a board meeting at 3 a.m."), but coordinating socially can be tricky.
"The hardest thing for me personally is getting up in the morning and immediately having to be on, first thing in the morning. There's no transition time," he said.
And with co-workers eight hours in the future but family and friends on Pacific Time, "You have to work a lot more at staying in sync with what's going on. You can't quite so easily integrate personal life into work life."
According to the Stanford Sleep Clinic's website, young adults and self-proclaimed "night owls" "appear to find it easier to adjust to night and nontraditional work shifts."
Palo Altan Chun-Wei Huang, 32, is one such night owl who said he's perfectly happy working and sleeping unusual hours, with a schedule that would be the worst nightmare (no pun intended) of a sleep clinician.
"I don't have a 'typical' sleeping schedule because it really depends on my projected workload and what I want to accomplish during the daylight hours here. I may pass out around 1 p.m. on some days and be awake by 7 p.m.," he stated in an email interview, adding that any Halloween trick-or-treaters ringing his doorbell will have better luck around midnight than in the early evening, when he'll likely still be "zonked out."
Huang works for an Asia-based green-energy venture, meaning he often has to coordinate with colleagues 15 to 16 hours ahead of him, along with frequent travel across many time zones.
"1 p.m. here coincides with the stock-market close, and 7 p.m. is currently 10 a.m. in Asia, so it gives my business partners there a chance to get caught up before we begin our Skype sessions. Sundays and Thursdays here are usually my busiest evenings because it is Monday and Friday afternoon in Asia," he said.
Huang has been working irregular hours and days since 2001 and said he has long since gotten used to it.
"It's not difficult to adjust to this kind of lifestyle, although it's definitely not for everyone, but we are operating in a global business environment, so I would expect more and more individuals adopting this kind of pattern. Taking power naps help if I anticipate a long day ahead," he said.
Sleep has always come easily to him, so he doesn't feel his health is in jeopardy.
"Closing the window blinds helps. I believe I'm a heavy sleeper, as some have said that I could probably sleep through World War III if it was going on outside. I grew up drinking green tea so caffeine has no impact in my system. I could say the same for sugar, too. This helps a lot, especially when I meet with friends for their lunch (my dinner), and we end up going to Starbucks afterwards. I could have an extra shot or a Venti mocha Frappuccino and still naturally fall sleep shortly afterwards," he said.
Huang, like Shaikh, sees some benefits to keeping his hours.
"My schedule actually makes grocery shopping easier, since I can go during off-peak periods. It's great that the Safeway stores around here are open 24/7. The benefits to going late at night during the graveyard hours: no traffic, no parking issues, no lines at the checkout counter and that all shelves have usually been restocked," he said.
"There's a money-saving benefit to beginning a meal after 9 p.m. Some restaurants on Castro Street in downtown Mountain View ... will bring back their discounted lunch specials menu."
Having a local social life can be tough at times, but "if I get advance notice, I can plan to stay awake ahead of time so that I'm not asleep when everyone else wants to go check out a new place and grab a bite to eat. I do miss out occasionally on the spontaneous road trips and last-minute group gatherings because I failed to answer the phone," he said.
"I definitely don't sleep enough, but that's the tradeoff I've accepted in hopes of a stock-option windfall and ... a somewhat balanced social life."
No matter how consistent their usual work schedules may be, new parents find themselves turning into shift workers of sorts, and often-unhappy night owls.
"Since the beginning of time, having a young child equals sleep deprivation, which is a reality," said Jessica Michaelson, a clinical psychologist who specializes in working with parents on baby-sleep issues. Palo Alto's Blossom Birth resource center offers classes and refers parents having a particularly tough time adjusting to sleep disruptions to sleep experts, including Michaelson.
"Babies, particularly in the first three months of life, are awake around the clock, every two to three hours, so parents, typically the mother, also are awake at that same frequency," she said. During a regular night's sleep, the body goes through natural 90-minute cycles of deep sleep, light (REM/dreaming) sleep and brief wake-ups, but "with a baby you are not waking up based on your own natural cycles. It might come during a deep sleep so you have to awaken and your nervous system has to respond to that, so it secretes stimulating hormones like adrenaline and cortisol to get you awake," she said.
Being pushed into a stimulated, forced-awake state is stressful to the body and the psyche.
"Studies link prolonged sleep deprivation with increased risk for maternal depression. It decreases your ability to function well during the day; there are more accidents, difficulty with work and planning, and executive functions. That's why we have maternity leave and paternity leave -- because you're neurologically not capable of performing" at regular levels during the months following birth, she said.
Michaelson, who has two children of her own, recalled her own exhaustion during the day -- "the feelings of powerlessness. You feel like you don't know how you're going to be able to get more sleep barring having other people take care of your children. The exhaustion on top of powerlessness can be quite overwhelming."
She recommends that parents (who are able) nap during the day, along with their baby -- something she said some parents are reluctant to "give themselves permission" to do. Hiring help to assist with night feedings can also be a lifesaver but is beyond the means of many. Before a baby is 6 months of age, it is unrealistic to expect it to sleep through the night, but counselors such as Michaelson can step in with advice and techniques when families with older babies and toddlers are having a hard time adjusting to longer periods of "sleep-time" and "wake-time."
Regardless of how or when it's accomplished, she said, people should make time to catch 40 winks, or at least a catnap.
"You can make better decisions if you're well-rested. It's in everybody's best interest to get as much rest as they can."