A patient aged 57yrs, when she sleeps on her left side see horrific dreams and gets up with palpitations and breathlessness. She regularly do pranayam and meditation and light exercises and household work by herself. She works in a central government office. She works in a central government office.

Her BP, ECG, Sugar and Lipid profile normal. She regularly do pranayam and meditation and light exercises and household work by herself. She works in a central government office. What may be the cause?