The electrical resistance of the human body can depend on the moisture condition of your skin at the time of measurement. If your skin is wet, you could have a resistance of only about 1100 Ohms. With dry skin, the amount is much higher at around 495,000 Ohms. Keep in mind that these are only estimates found during research and should not be taken for exact science.
The electrical resistance of your internal body is much smaller at approximately 85 Ohms up to 575 Ohms.
When working with any kind of electricity, you need to make sure you are staying dry for optimum safety. This means if you are going to be working in a hot place where you will sweat, then take a towel with you, or take frequent breaks and dry off. If you get shocked while wet, you are much more likely to feel the jolt, and in some cases this can be the difference between life and death.
The amount of voltage is not the only danger in most cases, it's the amount of current (amperage) introduced into the human body that can kill. It only takes about .015 amps across the human heart to kill. That's it, .015 amps! So the bottom line is no matter how little the voltage might be, always disconnect power at the breaker, and then check with a meter at the wall outlet, switch, or whatever you are working on to make sure power is actually off. Have fun, BE SAFE, and always respect electricity.