var Exercise = (function(){
    var steps = 0;
    function increaseSteps(){
        steps++;
    }
    return{
        getTotalSteps:function(){
            return steps;
        },
        walk:function(){
            increaseSteps();
        }
    };
}());

Exercise.walk(); //will increase the the step + 1
Exercise.getTotalSteps() //will return the total number of steps walked