Nigerian startups. Forged in Fire

A few weeks ago, I spent 8 days in Dubai. During that time, I trained (running or swimming) for at least 6 of those 8 days. My performance was at its peak, and I felt great. On Monday, a few weeks ago, I returned to Accra on the early morning flight from Doha; I was tired, but not more than usual. I rested that day and then continued my training throughout the week. The problem was that I was more tired than usual. By Friday, I was completely fatigued. I rested on Saturday, Sunday, and Monday. I started running again, but the fatigue persisted, even after two 75-minute deep tissue massages and plenty of sleep and rest. I was still exhausted. I checked my heart rate after the 8km z2 run. It was elevated. I know the humidity is challenging, and the air quality is terrible, but it was frustrating to still feel tired and underperforming in my training. Then I realized. This time last year, I weighed 13kg more and was in much worse shape. But I was running in cooler climates like Dubai...