Absolutely yes.

I’m a beginner/intermediate runner. I did an 11 mile run a month ago and felt so damn good at the end of it.

Last Sunday, I was shooting for 9.5 but after 4 miles at a relatively easy pace I hit a wall like I haven’t hit since week 1 of my program. Walked for almost a mile and got my HR down and finished another 3 miles at a slower pace.

I run with one of those handheld bottles and refilled it twice. Had to walk up the hills and trot down.

Fast forward to today. A storm came through and pushed the humidity away for a few hours and I decided to do my run when I noticed a cool breeze and drier air.

It is my last day with tempo thresholds (not sure the name of workout, still learning) before my time trial this weekend. Warmed up for a mile or so and was able To speed up and hold a pace for .50 mile that I haven’t done since beginning of June(8:20-8:30). And then another 2.5 miles at sub-threshold pace (9:20-9:40).

I was sweating bullets though bc humidity was rising pretty quick with the sun coming over the clouds but I felt really good at the end. I don’t give too much attention to my garmin watch but I finally was able to hit 45 on my Vo2 max and it rated my workout as tempo and showed me as improving drastically.

TL:DR

Yes. One year ago, did a 5K at an avg pace of 8:12. Avging 9:44+ at any giving moment. The hotter/humid, the slower I lose speed and faster I get tired.

Nathan bottle water is a life saver. I swear i need gels for electrolytes and sodium for even 1hr runs.