One of the great myths of our time is that gyms are conducive to good health. Clearly, they are not. They remove extortionate sums from our bank accounts simply so we can mimic what cavemen did for free, raise our blood pressure in the process, and, if the gym has a swimming pool or jacuzzi, threaten us with verrucas and Legionnaires' disease.
Gyms are the kind of clubs Groucho Marx would turn his nose up at, owing to the fact they will have anyone as a member (as long as they agree to the joining fee and €60 a month thereafter).
In January, they are filled with sinners in search of salvation, flagellating themselves on a treadmill to atone for all the turkey they ate and booze they drank. Which means that this month, the gym is rougly 10 times worse for you than any other time of the year.
Last week, a bodybuilder stabbed two men at a London gym after one refused to get off a weights machine.
Thankfully, the victims are in a stable condition and the perpetrator has been arrested, but this is not the only example of gym rage.
In 2008, a mother and daughter were banned for life from David Lloyd clubs after a fight in an aerobics class over which way the fan was facing. The year before, a Wall Street stockbroker was accused of throwing a man off a stationary bicycle for grunting in the spinning class. The stockbroker was eventually acquitted.
As you can see, so-called health clubs can be very, very dangerous indeed. But if you feel you absolutely must go to the gym, then go prepared. Here, we present the gym rats you're most likely to run into -- and the "sweatiquette" on how to handle them.
The sign clearly states that the running machine should be used for no longer than 20 minutes per person during peak hours. Yet the display on the machine clearly states that the man has been on it for 45 minutes -- and has no intention of stopping.
A friend who once tried to disturb such a creature was told, aggressively, that he was "training to take part in an Ironman, and you are clearly not, so please leave me be". If this happens, take yourself to the punch bag, and imagine it to be the treadmill tyrant.
Beware people who put the running machine and cross-trainer on such low settings they are merely walking.
As they "exercise", the treadmill tortoise will fiddle with their BlackBerry, or the controls of the television monitor as they try to tune into the news.
In extreme cases, they will even read a magazine. Hand the treadmill tortoise an Ordnance Survey map that features a selection of leisurely country walks.
The over-zealous gym instructor
Fine in classes, not so much when having to watch over the gym. Naturally hyperactive, they find such situations uncomfortable, and will try to amuse themselves by flicking the gym radio between dance and R&B stations, at top volume.
When this bores them, they will approach members and enthusiastically ask if they can help them stretch. The best way to stop them from ever approaching you again is to accept, before lying down on the mat and sticking a particularly cheesy stockinged foot in their face.
Grunters and sweaters
With their machismo dented horribly after crashing out of their local strongest man competition, these giant lumps of boiled ham have been trying to make up for it ever since -- unfortunately, in your gym.
They will run like a gale-force wind, spraying sweat all over the equipment, which they might later attempt to clean up with an already drenched towel. The towel will be left for you to remove, as they then grunt their way through a series of weights. Best to ignore -- attention only makes them stronger. At least figuratively.
Slow swimmers in the fast lane
In the pool, avoid that sinking feeling by silently ganging up on the minnow with other speedier swimmers. Like a shiver of sharks, you will surround him or her, overtaking, sometimes in twos and threes, until they return to the splash pool.
Every gym changing room has one, preening and posing while the rest try to get out of their leggings behind a towel.
The only way to avoid them is to stop going to the gym and exercise outside instead. It's cheaper, and you're unlikely to find a naked stranger hairdryering their entire body in your bathroom afterwards.