Sometimes despite your best intentions, life gets in the way of your fitness and health endeavours. There are ways to shorten your workout time without compromising intensity or results.
1. Trim your workout - a lot of resistance exercises duplicate the muscles being used, for instance a Chest press whilst targetting your chest, also works your shoulders (deltoids) and triceps, so there may be overlapping if a shoulder and a triceps exercise is then performed. Eliminate any overlapping and you can work all major muscle groups in 20 minutes and just 2 workouts a week
Day 1 - Squats, Bench Press, Bent Over Row, Plank
Day 2 - Deadlifts, Shoulder Press, Lat Pull Down/Pull ups, Russian Twists
Perform 3 sets of 8-15 reps dependant on your goals.
2. Supesets - If you look at your workouts honestly you will find that you probably spend half of your time resting between sets. You complete a set, rest for up to 60 seconds, then perform a second set, if you cover 25 sets in your workout you could be spending upwards of 25 minutes doing nothing, hardly efficient time management. Supesetting eliminates so much time wasted and halves your overall workout time, by pairing up exercises. By moving from one exercise to another without rest you also increase the overall intensity of the workout. When pairing exercises look at differing movements such as squats and bench press, Shoulder Press and Deadlifts etc
3. Workout Early - If you cannot find time to workout during lunch or after work, get up extra early and hit the gym before work. You may find that you have more energy throughout the day and experience an increase in your metabolic rate.
4. Sprint for it - Long slow Cardiovascular training is the most common seen in gyms, whilst this has its health and fitness benefits it isn't very time efficient. Switch to interval training, alternating periods of normal intensity with those of a high or even very high intensity, for example jogging interspersed with hard sprints. An additional benefit of such training is that it elevates your post exercise metabolic rate far more than long slow cardio. To begin with try 90 seconds of normal intensity followed by 30 seconds of harder work, repeat 5-8 times. As you progress you can work down the normal intensity time until equal, then perform 30 secs:30 secs or 1 min:1 min or 2 min:2min. Intensity is vital to interval training, so you must push yourself in the harder sections.
5. Workout at Home - Just getting to the gym can use up a lot of valuable workout time, so maybe you should consider working out at home, you don't even need any equipment, maybe just a towel. Perform star jumps and step ups to warm up, then perform bodyweight exercises, squats, press ups, lunges etc increase the intensity by introducing jumping/ plyometric versions. Perform all body exercises such as Burpees
So now with a little commitment and imagination you have opportunity to use a lack of time for your inability to grab a workout