Your dog might be hyperactive or look stressed for many reasons. Sometimes because a health problem, others just because he needs more exercise. There are also some breeds more active than others, like hunting dogs.
If you notice an abrupt change of behavior you should ask your vet. He or she will recommend you what is best in each situation.
In general, some recommendations to help your dog relax are:
Your dog needs to go out time enough to play and relax, not only to do his or her things. Go for a walk, play fetch, run... or just let your dog play with other dogs.
If your schedule is crazy and you cannot spend that much time with him, there are alternatives: dog walkers, day care or a friend who can give you a hand until you are back on track.
2. Interactive toys
You should never use them to substitute the daily exercise, but they do help your dog to think and relax. Try to hide things around the house (treats or toys), or buy one of the many interactive toys available in the market.
OK, some dogs hate it! Then you should forget this option as a "relax activity". But if your dog loves bath time, or grooming, use this moment to help him relax. Pet him and give him some treats.
There are some products like collars or sprays with synthetized pheromones that help dogs with fear. They are very helpful with dogs that are scared of the vet, or the car.
This is not a solution for hyperactive dogs that don't get all the exercise that they need, only for dogs that are stressed or scared by certain situations.
5. Natural supplements
In some cases, the vet might recommend some supplement to help your dog relax. He will probably recommend some natural options, as the use of drugs is limited to very extreme cases.