Training to ride your bike fast will not only increase your cycling pleasure and improve your overall skills; it will also increase your general fitness level. Cycling for fitness should include speed training in your training plans. Don't start speed training until you have built a good fitness level. Look at your fitness like a pyramid. The broader the base the greater peaks you will reach.
I hadn't expected to feel like a movie star. But as our 4x4 manoeuvres past hulking boulders of black volcanic rock as big as cars, I half expect to see Anne Hathaway strolling around the corner in her Interstellar spacesuit, or Bruce Willis drilling away, as he does in Armageddon. So, can't afford space travel? Come to Djibouti.