Best Time to Exercise According to Science: Morning vs Evening Workout. The best time to work out is a hotly debated topic. Some people think that waking up early for a morning workout is best while others think that afternoon or evening is better. Instead of relying on opinions or bro-science, let’s look at some quality studies to see what the research suggests. At the end of the day, remember the key is to find the time and routine you can stick to!