This is actually a simple relationship, which is often misunderstood by many people. High risk does not necessarily mean you will get a high reward. High risk means the potential for loss is high. At the same time, the potential returns can be high. If you are taking high risks, it is important to decide before hand when you are going to say quit.
Most people take high risk without knowing it, lured by only the potentially high reward.
Such actions usually end up in disasters. If you want to climb mount Everest, you should be properly equipped to do so. By contrast, low risk can be expected to generate low returns. Low risk means potential for loss is low. Therefore before investing your hard earned money or while planning to build long-term capital, one must closely examine the risk profile of any investment proposal.