I find that if I climb the day after a long or difficult run or other aerobic day that almost immediately my heart rate spikes, I’m winded, basically the aerobic juices are all used up. If I was trying to concurrently improve in climbing and aerobic fitness, I would be very deliberate how I layed out my weeks and micro training cycles. For example, Day 1 Rest, Day 2 Climb, Day 3 Run/Aerobic works because the climbing on day 2 is not taxing enough to adversely affect the running on day 3, but if I swap day and run on 2 and climb on 3 the Day 3 climbing session is not productive.
