We tend to associate cardiovascular training with boring plods round the park. But cardio work doesn't just mean running, while variation – as our list of alternatives shows – is key. It's been drilled into us that, if we want to sculpt an athletic frame covered in lean muscle, then a healthy balance of cardiovascular exercise and resistance training is the answer. Thrashing out the reps and carrying out the 'mirror exercises' (where you get to see your abs and biceps begin to bulge before your very eyes) can quickly become the preoccupation, while cardio (more often than not running) starts to seem like a chore. But it shouldn't be that way, and personal trainers everywhere will stress how important cardio is to all of us – not just for our physiques, but also our overall health. Personal trainer Jacob Nadav says: “Healthy cardiovascular is being able to maintain a reasonable level of activity without getting short of breath. Whether it's running, cycling, climbing up stairs or just constantly moving boxes, we are meant to be active and if your heart and lungs can't support you in doing so, you have some work ahead of you.” Despite the fact that cardiovascular exercise plays an essential part in protecting us against heart-disease (still the UK's biggest killer), British men just aren't doing enough of it. According to a recent British Heart Foundation survey, 45% of men in Scotland meet recommended levels of physical activity (30 minutes a day five times a week), compared to 39% in England, 37% in Wales and 33% in Northern Ireland. It's time to stop fearing cardio, or viewing it as a burden. Mix it up by trying some of these heart-boosting activities. Five-a-side football Exercise is exponentially easier if you are having fun, and there are few things more entertaining than smashing balls past your mate in goal during a game of fives. Five-a-side pitches are springing up all over the country, as canny investors snap up suitably large buildings and transform them into mini-theatres of dreams. And while you get to pretend you're Lionel Messi, your ticker gets a great workout. Nadav says: “Fives is a great way to maintain and improve your level of oxygen intake. The constantly changing pace of the game can really help restore and boost your basic cardio levels, in a similar way to something like Fartlek training.” Calories burned in an hour (average 82kg male): 800 Squash Off the treadmill, and onto the court. Few activities can match the cardiovascular benefits of squash, which requires bursts of speed and high levels of fitness to cope with the intensity of long rallies spent dashing round the court. “A good, intense game that will really push your CV [cardiovascular] system,” says personal trainer Pete Griggs. Remember to stretch those leg muscles before you start – otherwise your backside and thighs will throb the day after. This also increases blood flow while you exercise, encouraging better calorie burn, and allows you to move more freely on the court. Calories burned in an hour: 850 Boxing Boxing clubs are on the rise, but don't worry – you don't have to step into the ring and actually fight someone. Follow the training, however, and you'll get one of the most rewarding cardio workouts around, as well as the body you've probably always wanted. The sheer muscle flexing and calorie-incinerating nature of jumping rope, shadow boxing, doing endless burpees and push-ups is enough to boost your strength and endurance in ways you could never match by going for a jog. Boxing is also, as Griggs says, “great for letting out some aggression after a bad day at work,” even if you're not risking your pretty face. Calories burned in an hour: 900-1,000 Spinning Sitting atop a stationary bike and pedalling away might not seem any more engaging than putting one foot in front of the other round your favourite running track, but spinning has evolved into a much more targeted form of exercise since it first came on the scene. Look out for spinning studios, which hook you up to a heart rate monitor and ask you to flit between varying heart rates zones, as this type of athlete (that's you) specific upping and downing of intensity is exactly what you need to improve your cardiovascular fitness. Calories burned in an hour: 600-700 High Intensity Interval Training (HIIT) HIIT, like spinning, alternates between short bursts of intense activity with periods of lower intensity, forcing your heart rate up and leading to massive calorie burn, even after you've stopped working out. If you don't know what you're doing, then boot camps or military fitness sessions are an effective introduction. Once you start to feel the benefits, you'll never look back. Nadav says: “HIIT is a great option to improve cardiovascular fitness and lose weight when done correctly. Just one word of caution – it is very intense, as the name suggests, and not everyone can go to that level without any associated risks, so make sure your fitness levels are up to it.” Calories burned in an hour: 900-1000 Swimming Just because you can't feel the sweat pouring off you, doesn't mean you're not getting a satisfactory cardio workout. Nadav says: “Swimming is great at maintaining your basic level of cardio fitness, and it's a good option if you've got some joint problems as it's not weight bearing. It also allows you to control the level of intensity most of the time, while also being aerobic, which makes it great for burning fat.” Calories burned in an hour: 800 CrossFit “A good CV workout that incorporates all your muscles from head to toe,” says Griggs. It certainly is. CrossFit is a strength and conditioning programme, used by US police academies (yes, like the one Mahoney and Hightower went to), which combines weightlifting and sprints to explosive effect. Varying your workouts is important, but variation within sessions is also a good way to keep your muscles guessing and shifting your heart rate up a notch. Calories burned in an hour: 800-900 Tennis No doubt Wimbledon has inspired you to pull on the whites and dust off your racquet, so you may be one step ahead of us already. Much like squash, tennis relies on short bursts of speed and, once you've learned to stop hitting the ball to cow corner every time it comes your way, will give your aerobic and cardiovascular fitness a huge boost. If it can do what it did to natural skinny Andy Murray's physique, it can do the same to yours. “It's also a good alternative to squash if you have joint problems,” says Griggs. Calories burned in an hour: 600 Rugby Want to get ruck hard? Rugby isn't to everyone's taste, what with the cauliflower ears and cracking skulls together, but there's no denying the fact that modern rugger players are about as close as you can get to the ultimate athlete. Amateur you may be, but you can still benefit from the training, even if it's just to play the odd touch or pick-up game. Rugby training, and the matches themselves, promote speed and power and, of course, optimum cardiovascular health. Calories burned in an hour: 700 Walking Not the most intense of activities, but it's something you should certainly consider if you have an aversion to exercise or are just starting out on your fitness regime. It's also a way to get you out of a gym and into the great outdoors, so you won't really feel like you're being made to work for your improved health. Crucially, it will also get your heart rate up, and vigorous walking will burn calories to the tune of… well, just look at the number below. Calories burned in an hour: 400-500