Case study one

Barry Gibbs: Consultant
Barrry drives his Audi A4 TDi Avant 35,000 miles a year in his job as a consultant for the packaging industry. He traveled 220 miles from Tetbury, Gloucestershire, to Burton-on-Trent in Staffordshire and back in four hours, 43 minutes. His highest heart rate was 85bpm and average 62bpm.

1 76bpm
Im probably stuck behind someone at this point. I get agitated if Im in a hurry.
Expert Overtaking forces your heart rate up. Dr Lisa Dorn, an academic specialising in driver behaviour at Cranfield University, proved that by hooking up 31 people to a driver simulator and having them overtake a bus on a curved and hilly road: Their average heart rate was 80bpm, rising to 84bpm when they saw the bus. During the overtaking manoeuvre it went up to 88bpm.

2 85bpm
This was on a dual carriageway with no traffic but there were plenty of speed cameras and Im already on six points. If Im late Ill usually just drive faster.
Expert The growth of speed cameras gives drivers one extra thing to worry about. Coupled with the overtaking, it makes for a potent stress cocktail. A driver doing many complex manoeuvres over a long period of time with the added burden of time pressure might experience more stress, says Dr Lisa Dorn. The only known cure? Drive more slowly.

3 55bpm
This is on the M5 with very light traffic, which would explain why Im so relaxed. This is when I can feel sleepy and sometimes stop for a nap.
Expert The very low heart rates show theres little or no tension to stave off sleep. According to Dr Paul Jackson, MD of risk advisors Awake, the afternoon is a dangerous point in the day. During a long drive back after a stuffy meeting, the brain sends signal for the body to relax, he says. Taking a nap is a good idea, but a caffeinated drink also works. The main problem is the monotony of the road.