The pace you can sustain for a marathon depends on several factors and covers a wide range depending on your ability. The first is how quickly you can realistically do the marathon. For world-class athletes that finish a marathon in just over two hours it is possible to be very close to their lactate threshold (or red line)(80-85% of maximum effort). For athletes that take longer the effort level generally should be lower. This is partly due to duration and partly due to the fitness level of the individual. Highly trained individuals can sustain higher levels of intensity for longer periods of time. It is a good idea to operate within a range and this is generally between 60-80% of maximum effort. If you know your heart rate zones then it should be easy to match this effort with a heart rate range that is suitable for you.
Posted in: Goal Times and Effort