Some form of High intensity training is needed to trigger body response that is associated with health, like hormone release/sensitivity and muscle growth. Deadlifts is an excellent exercise if done correctly. But there is of course a plethora of exercies you can do, you have to find what works best for you. A 15 minute walk is not enough, humans are very good at walking, you will burn more energy doing 1 deadlift then walking for 15 minutes.