Is Kokoda as demanding as the Tour De France???

The harsh physical demands of the track were written about during times of war but have never been fully understood or quantified. The track runs for 96 km through dense rainforest, boggy swamps, tall grassland, and rises to over 7,000 ft at its highest point. The slopes are extremely steep, footholds uneven and paths narrow to less than a meter, often above sheer cliffs. Just to keep you on your toes the daily tropical rainstorms for much of the year ensure slippery conditions underfoot. On one day the track runs through smelly, ankle-deep swamp for up to 10 hours. River crossings are essential but present significant challenges especially during the monsoon season when flows increase.

Last week the School of Health Sciences Professor - Kevin Norton – followed a group of 6 walkers from South Australia as they walked the Kokoda track so that the physical work could be measured. Professor Norton had performed health and fitness testing in the laboratory on each person before heading off to New Guinea. They were all allocated a heart rate monitor that they wore continuously on the expedition.

Overall the average weight lost was around 5 kg. In general, the largest people lost the most weight. Everyone reported losing their appetite over the walk as they succumbed to the heat and oppressive conditions of the tropics. Quality sleep was also problematic. The energy expended in climbing the steep slopes carrying water and other provisions was enormous. The work undertaken to complete the track is summarised [as average values across the 6 walkers] in the figure.

As a basis of comparison a number of studies around the world have shown that for health benefits we should try to expend at least 150 kcal per day in exercise. This equates to about 30 minutes of walking. A very intense exercise session for an hour in the gym might require up to 600 kcal. On the Kokoda track, where days stretch to between 7 – 11 hours of walking, the energy required for exercise averaged 4,200 kcal per day. On the first day the energy used was almost 6,000 kcal per person! This is a massive rate of energy use and not much below the energy required by the Tour de France cyclists [about 6,000 kcal per day for 21 days]. To lose 1 kg of fat requires 9,000 kcal of energy use. This means the Kokoda track required burning off about a kg of fat every 2 days. Coupled with a loss of appetite, it is easy to see how each person could lose 5 kg over the 8 days of walking. The preparation required by those considering the trek should not be underestimated. Very high levels of conditioning are required. In a group the week before our trek, 8 of 11 were evacuated out by helicopter as a consequence of poor preparation, low fitness and the resultant dehydration and extreme fatigue.