Ozone Exposure

Training hard can lead to some unusual pains for the amateurs we are.

We were all very surprised and a bit scared as well to experience chest pains while hiking. Thanks to Elodie, we know what happened now: Ozone exposure.

Ozone is in the lower atmostphere (the air we breath) an air pollutants created by cars emissions and other pollutants when there is sunlight. The more sun the more ozone and consequently ozone peaks are at the hotter hours around noon. And it is typically an urban pollution.

Of course, ozone exposure causes adverse health effects, lucky us. Symptoms of exposure include chest pain, but not only: feeling of irritation in the eyes, nose and throat, shortness of breath, and wheezing.

Outdoor activities are therefore not recommended when ozone levels are high.
But we did not know it and we did exercise in an urban area, on very sunny days and felt chest pains.
How do we check the level of ozone in HK?

The HKSAR Environmental Protection Department created an Index: The Air Pollution Index (API) than is monitored on a real time basis. Check the API out before going outdoor!
Besides, the website of the HKSAR Environmental Protection Department on Air is very clear and I highly recommend it.

To learn more about Ozone:
A very good Q&A on Ozone by the Dpt of Health of the State of New York Ozone Exposure 1
The WHO study on Ozone pollution Ozone Exposure 2
And an excellent summary of this study by Green Facts Ozone Exposure 3

Training 1: Section 1&2 of the Maclehose Trail

Sunday 23 August

Team members on call: Chloe, Elodie and Lorene
Special guest: Anne-Laure

Weather: Very hot weather signal

Objective: Section 1 & 2 of the Maclehose trail
Length: 24.1 km Difficulty: Easy and medium

For our first training session, we have a special guest, Lorene's friend, Anne-Laure from Biarritz. Therefore, we decide to take it easy and do section 1&2. It is all the more a good idea, that the very hot weather signal is on, and though the signal is on, it takes much more than that to stop Chloe and Elodie the warriors.


We meet at 10 am in Admiralty and start hiking at 11. It is indeed very hot. Section 1 runs smoothly, it is mainly road, flat, a nice walk around the reservoir, and no shadow. Elodie is walking ahead, normal she says, we only walk 24 km today.


After a long hour, we can catch a glimpse of the beautiful Long Ke Wan beach. However we also notice an unusual scene. There is the clear blue water, the many junk boats and, many people gathered on the beach while an helicopter lands on the beach. A few minutes later, the helicopter is gone and everything gets back to normal.
One hour and a half of walk and we stand on Long Ke Wan. It is just so hot, we cannot resist to jump in the water before lunch, and it feels so good. It is a popular spot for lunch, many fellow walkers next to us. We try not too stop too long though, 30 min break and we start again.

It is now that is gets hardcore. The weather gets hotter and hotter, we are digesting and a there is a hill of 300 m up. 300 little meters that take us hours. Lorene is the only one to notice the board at the beginning of the hill mentioning heat exhaustion and precising that many hikers experienced difficulties on it because of the heat. Because of the heat, we need to stop every 20 min to cool down in the shadow and drink a lot of water. We all feel a little bit dizzy. Who said doing the Oxfam Trailwalker would be easy!!

But we are not alone, at each shelter we meet fellow hikers who train for the Oxfam Trailwalker. Who else could be hiking with this weather? We casually chat about the trai,l the weather. A very promising atmostphere. It seems that it is difficult for all of us today.

We finally manage to reach the top of this f..ing hill. Forget about the time, it took us ages. Thanks God we go downhill and the weather gets cooler. We are so tired, so late in our schedule that we would only finish section 2 past 9 pm. Besides, the sky gets very dark, we can hear the thunder and fellow trailwalkers tell us that it is raining in Shatin. There is just no way that we walk under the rain. At 4:30 pm we call it a day. At 5 pm we are in the bus, Alleluiah!!!

The bus drops us in Sai Kung and as exhausted as we are, we take a cab. Not any cab. The "Dictee magique" cab. B-U-F-F-E-T, Buffet, our cab driver is learning English, F-R-E-E-W-A-Y, freeway. We are still trying to find the link between buffet and freeway.

At this stage, we believe we only did section 1, 10 km, in 6 hours. We are so far from our goal. I, Lorene, just think that we are still alive despite the heat. In fact, it appears that we did go as far as checkpoint 1, which is at one third of section 2, 17 km. And it was 35°c in the shadow while there was no sign of shadow on the trail. L'honneur est sauf. We were not that bad.

We really suffered but this was our first training and we got this feeling of accomplishment. We started training!!