What Causes Runny Nose Upon Waking Up?

Greetings. I am a fit, healthy 67 year old male who has been a runner from the age of 8 and never smoked. I don t have any health problems and I don t eat junk food or drinks. My resting HR is 50bpm and my PB is 120 over 70. I have monitors for these because I also coach runners and use the monitors to determine residual, aerobic fitness to plan training schedules. My question is this. A year ago I moved house and since then my proboscis has start leaking on a regular basis. It starts minutes after I get up but after a few hard blows it settles down until immediately after lunch when it starts again and I repeat the process. Ditto, prior to or immediately after dinner, either while I m out or at home. My flatmate has no such problems so I cannot assume that it s an environment issue. Any thoughts please. Kind regards, Paul Larkin.