There are a few reasons for this; hydrostatic pressure; buoyancy and resistance.
To start with let’s look at hydrostatic pressure, a property you cannot benefit from when doing land base exercise. This is the gentle pressure on the body caused by the water when you are in the pool. This increases the deeper into the pool you go, think of your body being gently squeezed by the water. This pressure, along with the movement of the water provides a gentle massaging effect around the body helping with a variety of ailments. As this massaging effect is equal around the body, it assists with circulation and blood pressure by helping the venous return. If you suffer with high blood pressure and the doctor has advised you are safe to take part in exercise, gentle water based exercises would be a good way to take part and may help to lower your blood pressure. As your circulation is being controlled by the water-there is no added stress on the organs- meaning that your metabolism is still working while you are exercising- this is often why you can feel really hungry after you have been to the pool! The gentle pressure temporarily relieves oedema and fluid retention by encouraging the fluid back into the circulatory system (you may need to use the toilet more after your class!). If you are an asthma sufferer (providing chlorine does not have an adverse effect on your asthma), the hydrostatic pressure around your chest while exercising will help to strengthen your respiratory muscles, along with a warm and humid environment should make exercising in the water comfortable.
Buoyancy is the “floaty” feeling you get when you enter the water, a feeling of weightlessness that can be well received especially when you are in the later stages of pregnancy. This is also of benefit to those who are overweight or have a problem with their joints. This is one of the reasons why water exercise is used in injury rehabilitation, as it reduces the weight being loaded onto the joints, which may be overload for land based exercise and provides temporary relief from aches and pains. Standing chest depth in water can reduce impact on the body by as much as 90%. The buoyancy will change your centre of gravity and therefore your body will be using core muscles to keep you upright, so you will be strengthening important muscles before you even start your exercise! This “floaty feeling” will promote a sense of well being during the relaxation phase of your class and will also help to slow down the pace at which you work at in the water, but don’t worry- the resistance will make sure youwork just as hard as if you were on land!
Resistance- the reason why walking in water seems pretty hard… infact it is 12 times harderthan if you were to walk on land, and the deeper into the pool you are, the stronger the resistance. This water property is what instructors use to create a great workout. When not using any water weights you have resistance from every angle, meaning that you are gently toning all areas of your body as you exercise, thus creating a balanced way to improve your fitness. Resistance will also help to slow down your pace, reducing the risk of injury or falls (you can’t fall over in the water!). Adding resistance through water depth, water weights or changing your body position will help to provide more of a challenge- therefore the class can be easily adapted for everyone no matter what stage of fitness you are at!
The water temperature will keep you feeling comfortable throughout your class, meaning you can work harder during each asana (yogic posture), without necessarily feeling it. The calming effects of the water, combined with your yogic relaxation and breathing techniques will ensure that you do not leave your class feeling flushed, hot and sweaty but peaceful, invigorated and empowered (albeit slightly hungry!)