Antonyms for the phrase "strained oneself" can include relaxed, rested, rejuvenated, reinvigorated, refreshed, or renewed. These terms are all related to taking a break or resting in order to replenish one's energy levels. If someone strains themselves, it could lead to physical and mental exhaustion, which can lead to burnout and stress. By taking breaks and allowing oneself time to recharge, individuals can avoid becoming overwhelmed and fatigued. In today's fast-paced world, it is more important than ever to prioritize self-care and ensure that our bodies and minds are well-rested and nourished.