Originally Posted by python38
I'm not overweight, and look quite slim, but I don't feel very healthy on the inside, if that makes sense.
Clean up your diet and get plenty of exercise and your body will follow suit.
Originally Posted by python38
Also, how do I improve my diet? Is it worth drinking a lot of water all the time like some people recommend?
Eat more fruit and veg, get a decent portion of protein into every meal (ie; meat, fish, eggs, dairy, beans, lentils, etc), get a decent amount of low GI carbs (ie; beans, lentil, oats, wholewheat pasta, brown rice) and cut back on (or cut out entirely) processed food. How you do this is up to you, if you can manage a complete transformation overnight go for it, if you can't then change things gradually, concentrate on gradually substituting your snacks and meals for progressively healthier alternatives.
Water. The majority of the people who talk about consuming vast quantities of water don't have a clue what they're talking about and their advice can actually be damaging. Consume fluids until your urine is a pale yellow colour. Dark yellow and stinky - you're dehydrated, increase your fluid intake. Very pale or even colourless - you're overhydrated, decrease or even stop your fluid intake. If you ever get headaches, you're passing large amounts of colourless urine and you're drinking a lot stop taking on fluids immediately.
Originally Posted by python38
I'm 15, and way too weak for my age (I can't even do a full press-up.)
What are some good exercises I can do with no equipment? I used to lift light weights, but I won't be having access to those very soon. How often should I be training? Is it worth doing stuff like running and cycling as well as pure strength exercises?
At the end of the day it depends on what you want to achieve. If you want to get stronger, perhaps put on a bit of muscle and lose a bit of fat then resistance training (eg; weights) is going to be the main port of call. If you want general all round fitness then it could be a good idea to integrate some HIIT/cardio.
Start gradually, if you're a complete novice it's pointless jumping into a 7 day routine, you will burn yourself, will achieve very little and may even injure yourself. Consistency and gradual progression over a long period of time is the key.
As a general rule at the beginning stick to a basic 3 day full body workout, one big lower body exercise (ie; deadlifts, squats, lunges, stepups), one big upper body push (ie; overhead press, dips, pushups, bench press) and one big upper body pull (ie; rows, chinups, pullups). Starting Strength, Stronglifts (there is a dumbbell version of the main routine), Westside for Skinny Bastards, Never Gymless and Infinite Intensity are all good programs. Then after several weeks it could be a good idea to integrate a day of HIIT per week.
In terms of equipment a pullup/chinup bar is a must really. Some adjustable dumbbells would are also pretty cheap and would certainly open up your options significantly. At the end of the day most of the routines mentioned require quite a range of kit so in some ways it can be a good idea to join a gym unless you're in it for the long haul and are adamant that you will get plenty of use out of the kit (and have the money to spare).
Originally Posted by python38
Finally, how much sleep should I be getting?
Around 8-10 hours is the ideal.