Joe Friel (Fast After 50) - Research suggests that 60 to 70 percent of age related decline is related to our training habits.

Tends to increase with increasing age. Athletes stop their interval and speed workouts. For people with health problems, this makes sense. But many of us would be better served by going hard once in a while.

Comfort and experience - some people have never actually trained with intensity. Worry that they'll do it wrong, or that it can hurt them when it's actually not doing it that hurts them.

Avoiding discomfort - if we can get the same results without pain, we'll take it! Except that we can't.

Going slow is not a bad thing. You learned way back in episode #1 that your first priority as an outdoor athlete is to build your aerobic base, which means just having a lot of time on your feet. You also will be moving slowly during your goal hike if you pace yourself right. However, working on speed will actually make that slow hike more comfortable.

To go fast, we need to train different energy systems than we do to go slow. See my episode on lactate threshold. We also want to work on our VO2 max, which allows us to use more oxygen. This means doing some interval training.

At least 8 weeks of base fitness (aerobic system will be ready before muscles, joints, connective tissues)

For beginners, ease in! Start with fartleks, which are playful. Run to the lamppost. Run to the goose. Powerhike up a short hill. Less than a minutes, recover in between. Add LT, then HIIT in layers to allow your body to get used to this type of hard work/discomfort.

Resources:
Episode on LT workouts
Mountain Fit walks you step by step through how to design these workouts – how long to work, how long to rest in between, how many to do, how to progress them. The interval tables are probably some of the most useful things in there. They're what I use when I'm writing workouts for my 1:1 clients.

If you have some experience, start with HIIT intervals (short, very intense intervals lasting 30 seconds to 3 minutes). The reason for this is that they raise your VO2 max. Your VO2 max is the absolute limit of how hard you can work. In a lot of recreational athletes, your VO2 max sits right on top of other thresholds like your lactate threshold. So even though it seems counterintuitive, doing the most intense work first actually helps you. Progress to lactate threshold work and use your specific period to emphasize base and distance.

Check in with a doctor before doing maximal exercise, especially if you have any significant health conditions. The most dangerous period for cardiac events is when you're starting an exercise program after being sedentary. Risk increases with exercise intensity. Not everyone should do maximal exercise, and that's OK.

With intensity, a little goes a long way! As you learned in episode #1, 80 to 90 percent of your training should be lower intensity base workouts.