Men and women were meant to be active. Confine them to a sedentary life and they develop all kinds of ailments including diabetes and high blood pressure. They need to run, swim, or engage in any sport requiring physical exertion. For an extra dose of excitement, they can go mountain climbing or biking, or white water rafting.

White water rafting has been gaining in popularity since the 1970s. Today, hundreds of tourists eagerly plunge into the white waters of rivers across the Americas, from Canada down to Chile; in Europe, from England to Turkey; in Africa, from Morocco to Zambia where the great Zambezi River flows into the Victoria Falls; and in Asia, from Nepal to Indonesia and even the Philippines.

Where there is a steep drop in the gradient of a river, the smooth water flow is disturbed. The flow speeds up considerably and creates bubbly white water. Sometimes there are huge boulders strewn all over the river. Some are above the water while others are submerged. These result to tall waves, eddies, holes, strainers, and sieves that rafters must take on. Avoiding the exposed boulders pose an additional challenge.

Rafts used for the sport are the inflatable type. They are often made of rubberized or vinyl fabrics. To prevent the total loss of air when punctured, the air chambers are divided into separate compartments. These can accommodate from 4 to 12 people with their varying lengths from 3 1/2 to 6 meters, and width from a little below 2 meters to 2 1/2.

To standardize the classification of the difficulty in running river rapids, the International Scale of River Difficulty was established. This consists of six Grades or Classes ranging from I to IV, described thus:

• Class I. Easy – waves are small with virtually no obstructions.
• Class II. Medium – moderately difficult rapids requiring some experience in rafting.
• Class III. Difficult – numerous high waves, eddies, rocks and boulders obstructing passage that need maneuvering expertise along with a good and sound raft.
• Class IV. Very Difficult – long rapids with high and irregular waves, sharp rocks with narrow openings in between, and huge eddies.
• Class V. Extremely Difficult – an almost uninterrupted series of long and violent rapids, rocks and boulder obstructions, steep gradient and even moderate drops, wild and turbulent current, all requiring an expert rafter as this is extremely dangerous and could even be fatal.
• Class VI. Unrunnable – extremely steep gradients and tall drops.

As with any other sport there are measures and equipment that could be employed for a safer white water rafting adventure. First is not to attempt to challenge a river rapid beyond your experience and capabilities. If it is your first time do not presume to take on a Class V or even IV. Go for the gentler ones and gradually work your way up. Also, listen to your guides. Their experience and knowledge in this area are your guarantee of an exciting yet challenging adventure. Finally, do not forget your helmet and personal flotation device (PFD). A rope bag, whistle, and a knife could also come in handy.