Timing is everything when it comes to life - literally. Our bodies run to a tightly regulated schedule, a daily biochemical to-do list controlled by master clock genes that ensure things happen only when they should.
The secrets behind this rhythm of life will be explained next Thursday at a Science Today lecture at the RDS, Ballsbridge, Dublin. The reasons why we get jet lagged, why shift- and night-work is so tough and why driving in the very early morning can be so dangerous, will all be revealed by guest speaker, Prof Russell Foster.
Prof Foster is one of the world's leading experts on human circadian rhythms and how they are enacted at a biological level. He is professor of molecular neuroscience at ICL and research co-ordinator at Charring Cross Hospital in London.
He oversees an extensive research programme at ICL conducted within the university's faculty of medicine. It aims to better understand the links between our genes and our general health.
He will explore the general subject in a lecture entitled, "Rhythms of Life - doing the right thing at the right time". He will draw on ideas raised in his new book, Rhythms of Life, The Biological Clocks that Control the Daily Lives of Every Living Thing, co-written with Leon Kreitzman.
Sleeping, eating, digesting, even thinking, are influenced by the master clock in the front of the brain, the suprachiasmatic nuclei, Foster will tell those attending his lecture next Thursday. This cluster of cells acts like "a radio time signal", sending out information to the rest of the body, he explains. "It is the master clock but must be adjusted to the local time, and the light/dark cycle does that."
To say that it has an influence is an understatement. The signals the master clock sends out reach other clock genes right across the body. "On average the human clock under constant conditions gives a day of 24 hours 11 minutes, a little bit longer than an astronomical day," says Foster. The clock constantly adjusts itself by responding to light entering the eye. Clock genes influence things right across the body, he adds. "These changes are not trivial."
The master clock varies blood pressure up and down, affects alertness and physical performance, speeds up or slows down digestion and pushes us towards periods of wakefulness and sleep. Recent studies of how clock genes regulate these has thrown up some interesting findings.
Driving between 4 a.m. and 6 a.m. is more dangerous than at other times, for example. This period is a low spot for alertness, with performance "worse than if you were legally drunk", says Prof Foster. "When driving between four to six in the morning your ability to make decisions is as hard as if you have had a couple of whiskeys."
Peak sports performance by comparison, arrives at between 6 p.m. and 8 p.m. in most people, just at the time when the daily body temperature reaches its highest. Long-jumpers perform best at about 6 p.m. Swimmers, however, do best a bit later at 8 p.m., with a 100-metre sprint up to 2.7 seconds faster than if the swimmer does the same distance at 6 a.m.
"Clocks evolved shortly after life evolved on Earth," says Prof Foster. It was an evolutionary adaptation driven by a "massive selection pressure" dictated by the rise and fall of the sun.
Prof Foster's lecture, organised by The Irish Times and the Royal Dublin Society, takes place in the RDS Library at 6.30 p.m. on Thursday, April 1st. Tickets for the lecture are free but must be booked in advance by telephone.
To book, call 1550-114-709, or 0906-604-0249 from Northern Ireland, leaving your name and phone number and the number of seats you require (maximum two seats per person). Calls cost 74 cent per minute, and calls from mobile phones may be more expensive. The phone lines will remain open until the 300 seats available at the lecture are fully booked. Tickets are not available directly from either The Irish Times or the RDS. Please note that tickets will not be issued, but the booking confirms your place at the lecture.
