One common reason people with HIV give for not embarking on an exercise programme is fatigue or lack of energy.
Whilst it is true that HIV infection, medication and co-infections can cause a drop in energy levels, it's also important to remember that (clinically-related fatigue aside) the more energy you use, the more your body provides you with. Fatigue and lack of motivation seem to be strongly linked - studies have shown that stress, depression, anxiety and poor coping strategies were all consistently related with greater severity of fatigue.
If you have little motivation in your day-to-day life and do little, your body gets used to this and develops an idea of what levels of energy are needed to manage your limited day-to-day activities. However, if you start to increase your activity levels slowly, your body will start using its energy stores more efficiently and increase its reserves to accommodate the increase in need.
A common problem is that people often throw themselves into an unrealistic programme of exercise and end up injuring themselves or wearing themselves out. This in turn makes them too anxious to try again. Starting gently and easily is the best way forwards, slowly building and increasing your activity bit by bit. A good way of checking this out is to set yourself a small goal to start with, check out how long it takes you to do it and how you feel. Then, continue to do this, either going further in distance or time as you progress, until you can see the improvement you've made and feel the benefits.
Once you've started exercising, maintaining it can sometimes be a challenge, so it's very important to find something you enjoy doing. If you're a sociable person, try including a friend or partner in the activity to keep you company and motivate each other while you walk, jog or cycle. Often, although self-commitment may fizzle out, we are less likely to quit if there's a commitment to someone else involved.
Group activities and classes can be a good way of making and keeping a commitment to yourself. Having a set time and day where you play tennis or go to a yoga, aerobics or dance class provides structure and routine, and you'll meet others who are trying to improve their health, and feel supported and more motivated.
Finally, if you have a period where you stop exercising, the trick into getting back on track is just to do it!
Try writing up a list of what you liked about exercising and how it made you feel, and then write another list from the negative perspective and see which one carries more weight (always remembering that the long-term benefits of exercise are not instantly noticeable).