I have beeing working on an oil rig for about 6 months now. I way 140 pounds at 5’8. I work 14 days in a row 12 hours shifts then I get 7 days off. I try to eat 4000 calories a day. all I can bring up are some dumbells. so im wondering what would be the best workout plan for me considering I work for 12 hours a day and come back to camp or the hotel pretty exhausted. so I would like to keep my workouts under half an hour while at work but when im at home for a week I have pretty much a full gym to workout .